500+ TOP Engineering Mechanics MCQs and Answers Quiz

Engineering Mechanics Multiple Choice Questions

1. A body of mass ‘m’ moving with a constant velocity ‘v’ strikes another body of same mass moving with same velocity but in opposite direction. The common velocity of both the bodies after collision is

A.v

B.2v

C.4v

D.8v

Answer: B

2. The bellow figure shows the three coplanar forces P, Q and R acting at a point O. If these forces are in equilibrium, then

A.P/sin β = Q/sin α = R/sin ɣ

B.P/sin α = Q/sin β = R/sin ɣ

C.P/sin ɣ = Q/sin α = R/sin β

D.P/sin α = Q/sin ɣ = R/sin β

Answer: B

3. The centre of percussion of the homogeneous rod of length ‘L’ suspended at the top will be

A.L/2

B.L/3

C.3L/4

D.2L/3

Answer: D

4. The angle of inclination of the plane at which the body begins to move down the plane, is called

A.Angle of friction

B.Angle of repose

C.Angle of projection

D.None of these

Answer: A

5. Pick up wrong statement about friction force for dry surfaces. Friction force is

A.Proportional to normal load between the surfaces

B.Dependent on the materials of contact surface

C.Proportional to velocity of sliding

D.Independent of the area of contact surfaces

Answer: C

6. The term ‘Centroid’ is

A.The same as centre of gravity

B.The point of suspension

C.The point of application of the resultant of all the forces tending to cause a body to rotate about a certain axis

D.None of the above

Answer: A

7. The C.G. of a plane lamina will not be at its geometrical centre in the case of a

A.Right angled triangle

B.Equilateral triangle

C.Square

D.Circle

Answer: A

8. If the masses of both the bodies, as shown in the below figure, are reduced to 50 percent, then tension in the string will be

A.Same

B.Half

C.Double

D.None of these

Answer: B

9. The moment of inertia of a thin rod of mass ‘m’ and length ‘l’, about an axis through its centre of gravity and perpendicular to its length is

A.ml2/4

B.ml2/ 6

C.ml2/8

D.ml2/12

Answer: D

10. Forces are called coplanar when all of them acting on body lie in

A.One point

B.One plane

C.Different planes

D.Perpendicular planes

Answer: B

11. A rubber ball is dropped from a height of 2 m. If there is no loss of velocity after rebounding, the ball will rise to a height of

A.1 m

B.2 m

C.3 m

D.4 m

Answer: B

12. A weight of 1000 N can be lifted by an effort of 80 N. If the velocity ratio is 20, the machine is

A.Reversible

B.Non-reversible

C.Ideal

D.None of these

Answer: A

13. Centre of gravity of a solid cone lies on the axis at the height

A.One fourth of the total height above base

B.One third of the total height above base

C.One-half of the total height above base

D.Three eighth of the total height above the base

Answer: A

14. The periodic time (T) is given by (where, ω = Angular velocity of particle in rad/s.)

A.ω/2π

B.2π/ω

C.2π × ω

D.π/ω

Answer: B

15. The resultant of two forces P and Q (such that P > Q) acting along the same straight line, but in opposite direction, is given by

A.P + Q

B.P – Q

C.P / Q

D.Q / P

Answer: B

16. When two elastic bodies collide with each other,

A.The two bodies will momentarily come to rest after collision

B.The two bodies tend to compress and deform at the surface of contact

C.The two bodies begin to regain their original shape

D.All of the above

Answer: D

17. The coefficient of friction depends upon

A.Nature of surfaces

B.Area of contact

C.Shape of the surfaces

D.All of the above

Answer: A

18. The angular velocity (in rad/s) of a body rotating at N revolutions per minute is

A.πN/60

B.πN/180

C.2πN/60

D.2πN/180

Answer: C

19. A block of mass m1, placed on an inclined smooth plane is connected by a light string passing over a smooth pulley to mass m2, which moves vertically downwards as shown in the below figure. The tension in the string is

A.m1/m2

B.m1. g. sin α

C.m1.m2/m1 + m2

D.m1. m2.g (1 + sin α)/(m1 + m2)

Answer: D

20. In determining stresses in frames by methods of sections, the frame is divided into two parts by an imaginary section drawn in such a way as not to cut more than

A.Two members with unknown forces of the frame

B.Three members with unknown forces of the frame

C.Four members with unknown forces of the frame

D.Three members with known forces of the frame

Answer: B

21. A machine having an efficiency greater than 50%, is known as

A.Reversible machine

B.Non-reversible machine

C.Neither reversible nor non-reversible machine

D.Ideal machine

Answer: A

22. The algebraic sum of moments of the forces forming couple about any point in their plane is

A.Equal to the moment of the couple

B.Constant

C.Both of above are correct

D.Both of above are wrong

Answer: A

23. In the lever of third order, load ‘W’, effort ‘P’ and fulcrum ‘F’ are oriented as follows

A.W between P and F

B.F between W and P

C.P between W and F

D.W, P and F all on one side

Answer: A

24. Which of the following statement is correct?

A.The algebraic sum of the forces, constituting the couple is zero

B.The algebraic sum of the forces, constituting the couple, about any point is the same

C.A couple cannot be balanced by a single force but can be balanced only by a couple of opposite sense

D.All of the above

Answer: D

25. A heavy ladder resting on floor and against a vertical wall may not be in equilibrium, if

A.The floor is smooth, the wall is rough

B.The floor is rough, the wall is smooth

C.The floor and wall both are smooth surfaces

D.The floor and wall both are rough surfaces

Answer: C

26. The skidding away of the vehicle on a level circular path can be avoided if the force of friction between the wheels and the ground is __________ the centrifugal force.

A.Less than

B.Greater than

C.Equal to

D.None of these

Answer: B

27. Coulomb friction is the friction between

A.Bodies having relative motion

B.Two dry surfaces

C.Two lubricated surfaces

D.Solids and liquids

Answer: A

28. The time of flight (t) of a projectile on an upward inclined plane is(where u = Velocity of projection, α = Angle of projection, and β = Inclination of the plane with the horizontal.)

A.t = g cos β/2u sin (α – β)

B.t = 2u sin (α – β)/g cos β

C.t = g cos β/2u sin (α + β)

D.t = 2u sin (α + β)/g cos β

Answer: B

29. Which of the following is the example of lever of first order?

A.Arm of man

B.Pair of scissors

C.Pair of clinical tongs

D.All of the above

Answer: D

30. Three forces acting on a rigid body are represented in magnitude, direction and line of action by the three sides of a triangle taken in order. The forces are equivalent to a couple whose moment is equal to

A.Area of the triangle

B.Twice the area of the triangle

C.Half the area of the triangle

D.None of these

Answer: B

31. The Cartesian equation of trajectory is (where u = Velocity of projection, α = Angle of projection, and x, y = Co-ordinates of any point on the trajectory after t seconds.)

A.y = (gx²/2u² cos²α) + x. tanα

B.y = (gx²/2u² cos²α) – x. tanα

C.y = x. tanα – (gx²/2u² cos²α)

D.y = x. tanα + (gx²/2u² cos²α)

Answer: C

32. The units of moment of inertia of an area are

A.kg-m²

B.m⁴

C.kg/m²

D.m³

Answer: B

33. The slope on the road surface generally provided on the curves is known as

A.Angle of friction

B.Angle of repose

C.Angle of banking

D.None of these

Answer: C

34. A force acting on a body may

A.Change its motion

B.Balance the other forces acting on it

C.Retard its motion

D.All of the above

Answer: D

35. The centre of gravity of an isosceles triangle with base (p) and sides (q) from its base is

A.[√(4p² – q²)]/6

B.(4p² – q²)/6

C.(p² – q²)/4

D.(p² + q²)/4

Answer: A

36. On a ladder resting on smooth ground and leaning against vertical wall, the force of friction will be

A.Towards the wall at its upper end

B.Away from the wall at its upper end

C.Upwards at its upper end

D.Downwards at its upper end

Answer: C

37. The velocity of a body on reaching the ground from a height h, is

A.2.√(gh)

B.√(gh)

C.√(2gh)

D.2g.√h

Answer: C

38. A framed structure, as shown in the below figure, is a

A.Perfect frame

B.Deficient frame

C.Redundant frame

D.None of the above

Answer: A

39. Lami’s theorem states that

A.Three forces acting at a point will be in equilibrium

B.Three forces acting at a point can be represented by a triangle, each side being proportional to force

C.If three forces acting upon a particle are represented in magnitude and direction by the sides of a triangle, taken in order, they will be in equilibrium

D.If three forces acting at a point are in equilibrium, each force is proportional to the sine of the angle between the other two

Answer: D

40. The ratio of static friction to dynamic friction is always

A.Equal to one

B.Less than one

C.Greater than one

D.None of these

Answer: C

41. Which is the correct statement about law of polygon of forces?

A.If any number of forces acting at a point can be represented by the sides of a polygon taken in order, then the forces are in equilibrium

B.If any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon, then the forces are in equilibrium

C.If a polygon representing forces acting at a point is closed then forces are in equilibrium

D.If any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon taken in order, then the forces are in equilibrium

Answer: D

42. Moment of inertia of a triangular section of baseB.and height (h) about an axis through its base, is

A.bh3/4

B.bh3/8

C.bh3/12

D.bh3/36

Answer: C

43. Coefficient of friction is the

A.Angle between normal reaction and the resultant of normal reaction and the limiting friction

B.Ratio of limiting friction and normal reaction

C.The friction force acting when the body is just about to move

D.The friction force acting when the body is in motion

Answer: B

44. The forces, which meet at one point and their lines of action also lie on the same plane, are known as

A.Coplanar concurrent forces

B.Coplanar non-concurrent forces

C.Non-coplanar concurrent forces

D.Non-coplanar non-concurrent forces

Answer: A

45. A flywheel on a motor goes from rest to 1000 rpm in 6 sec. The number of revolutions made is nearly equal to

A.25

B.50

C.100

D.250

Answer: B

46. A ladder is resting on a smooth ground and leaning against a rough vertical wall. The force of friction will act

A.Towards the wall at its upper end

B.Away from the wall at its upper end

C.Downward at its upper end

D.Upward at its upper end

Answer: D

47. Pick up the incorrect statement from the following:

A.The C.G. of a circle is at its centre

B.The C.G. of a triangle is at the intersection of its medians

C.The C.G. of a rectangle is at the intersection of its diagonals

D.The C.G. of a semicircle is at a distance of r/2 from the centre

Answer: D

48. The range of projectile (R) on an upward inclined plane is

A.g. cos² β/2u². sin (α + β). cos α

B.2u². sin (α + β). cos α/g. cos² β

C.g. cos² β/2u². sin (α – β). cos α

D.2u². sin (α – β). cos α/g. cos² β

Answer: D

49. If three forces acting in one plane upon a rigid body, keep it in equilibrium, then they must either

A.Meet in a point

B.Be all parallel

C.At least two of them must meet

D.All the above are correct

Answer: D

50. In order to double the period of simple pendulum, the length of the string should be

A.Halved

B.Doubled

C.Quadrupled

D.None of these

Answer: C

51. The angle which an inclined plane makes with the horizontal when a body placed on it is about to move down is known as angle of

A.Friction

B.Limiting friction

C.Repose

D.Kinematic friction

Answer: C

52. The energy possessed by a body, for doing work by virtue of its position, is called

A.Potential energy

B.Kinetic energy

C.Electrical energy

D.Chemical energy

Answer: A

53. The centre of gravity of a uniform lamina lies at

A.The centre of heavy portion

B.The bottom surface

C.The midpoint of its axis

D.All of the above

Answer: C

54. The three forces of 100 N, 200 N and 300 N have their lines of action parallel to each other but act in the opposite directions. These forces are known as

A.Coplanar concurrent forces

B.Coplanar non-concurrent forces

C.Like parallel forces

D.Unlike parallel forces

Answer: D

55. Angle of friction is the

A.Angle between normal reaction and the resultant of normal reaction and the limiting friction

B.Ratio of limiting friction and normal reaction

C.The ratio of minimum friction force to the friction force acting when the body is just about to move

D.The ratio of minimum friction force to friction force acting when the body is in motion

Answer: A

56. Moment of inertia of a hollow circular section, as shown in the below figure about an axis perpendicular to the section, is ________ than that about X-X axis.

A.Two times

B.Same

C.Half

D.None of these

Answer: A

57. The frequency of oscillation of a compound pendulum is (where kG = Radius of gyration about the centroidal axis, and h = Distance between the point of suspension and C.G. of the body.)

A.2π. √(gh/kG² + h²)

B.2π. √(kG² + h²/gh)

C.1/2π. √(gh/kG² + h²)

D.1/2π. √(kG² + h²/gh)

Answer: C

58. The necessary condition for forces to be in equilibrium is that these should be

A.Coplanar

B.Meet at one point

C.BothA.andB.above

D.All be equal

Answer: C

59. Two forces are acting at an angle of 120°. The bigger force is 40 N and the resultant is perpendicular to the smaller one. The smaller force is

A.20 N

B.40 N

C.120 N

D.None of these

Answer: A

60. In actual machines

A.Mechanical advantage is greater than velocity ratio

B.Mechanical advantage is equal to velocity ratio

C.Mechanical advantage is less than velocity ratio

D.Mechanical advantage is unity

Answer: C

61. Coefficient of friction depends upon

A.Area of contact only

B.Nature of surface only

C.BothA.and (B)

D.None of these

Answer: B

62. Moment of inertia of a hollow rectangular section as shown in the below figure about X-X axis, is

A.(BD³/12) – (bd³/12)

B.(DB³/12) – (db³/12)

C.(BD³/36) – (bd³/36)

D.(DB³/36) – (db³/36)

Answer: A

63. Which of the following is a vector quantity?

A.Energy

B.Mass

C.Momentum

D.Angle

Answer: C

64. The maximum velocity of a particle moving with simple harmonic motion is

A.ω

B.ωr

C.ω2r

D.ω/r

Answer: B

65. The product of either force of couple with the arm of the couple is called

A.Resultant couple

B.Moment of the forces

C.Resulting couple

D.Moment of the couple

Answer: D

66. The moment of a force

A.Is the turning effect produced by a force, on the body, on which it acts

B.Is equal to the product of force acting on the body and the perpendicular distance of a point and the line of action of the force

C.Is equal to twice the area of the triangle, whose base is the line representing the force and whose vertex is the point, about which the moment is taken

D.All of the above

Answer: D

67. A heavy string attached at two ends at same horizontal level and when central dip is very small approaches the following curve

A.Circular arc

B.Parabola

C.Hyperbola

D.Elliptical

Answer: B

68. The centre of gravity a T-section 100 mm × 150 mm × 50 mm from its bottom is

A.50 mm

B.75 mm

C.87.5 mm

D.125 mm

Answer: C

69. Kinetic friction is the

A.Tangent of angle between normal reaction and the resultant of normal reaction and the limiting friction

B.Ratio of limiting friction and normal reaction

C.The friction force acting when the body is just about to move

D.The friction force acting when the body is in motion

Answer: D

70. According to Newton’s first law of motion,

A. Everybody continues in its state of rest or of uniform motion, in a straight line, unless it is acted upon by some external force

B. The rate of change of momentum is directly proportional to the impressed force, and takes place in the same direction, in which the force acts

C. To every action, there is always an equal and opposite reaction

D. None of the above

Answer: A

71. Which of the following is not a vector quantity?

A.Weight

B.Velocity

C.Acceleration

D.Force

Answer: A

72. The mechanical advantage of a lifting machine is the ratio of

A.Distance moved by effort to the distance moved by load

B.Load lifted to the effort applied

C.Output to the input

D.All of the above

Answer: B

73. From a circular plate of diameter 6 cm is cut out a circle whose diameter is a radius of the plate. Find the e.g. of the remainder from the centre of circular plate

A.0.5 cm

B.1.0 cm

C.1.5 cm

D.2.5 cm

Answer: A

74. In ideal machines, mechanical advantage is __________ velocity ratio.

A.Equal to

B.Less than

C.Greater than

D.None of these

Answer: A

75. Frictional force encountered after commencement of motion is called

A.Limiting friction

B.Kinematic friction

C.Frictional resistance

D.Dynamic friction

Answer: D

76. The centre of gravity of a right circular solid cone is at a distance of _________ from its base, measured along the vertical axis.(where h = Height of a right circular solid cone.)

A.h/2

B.h/3

C.h/4

D.h/6

Answer: C

77. A particle inside a hollow sphere of radius r, having coefficient of friction µ can rest up to height of

A.r/2

B.r/A

C.r/3

D.0.134 r

Answer: D

78. Which of the following statement is incorrect?

A.A force acting in the opposite direction to the motion of the body is called force of friction

B.The ratio of the limiting friction to the normal reaction is called coefficient of friction

C.A machine whose efficiency is 100% is known as an ideal machine

D.The velocity ratio of a machine is the ratio of load lifted to the effort applied

Answer: D

79. A sample of metal weighs 219 gms in air, 180 gms in water, 120 gms in an unknown fluid. Then which is correct statement about density of metal

A.Density of metal can’t be determined

B.Metal is twice as dense as water

C.Metal will float in water

D.Metal is twice as dense as unknown fluid

Answer: A

80. The centre of percussion is below the centre of gravity of the body and is at a distance equal to

A.h/kG

B.h2/kG

C.kG2/h

D.h × kG

Answer: C

81. A cable with a uniformly distributed load per horizontal meter run will take the following shape

A.Straight line

B.Parabola

C.Hyperbola

D.Elliptical

Answer: B

82. When a body falls freely under gravitational force, it possesses __________ weight.

A.No

B.Minimum

C.Maximum

D.None of these

Answer: A

83. A body moves, from rest with a constant acceleration of 5 m per sec. The distance covered in 5 sec is most nearly

A.38 m

B.62.5 m

C.96 m

D.124 m

Answer: B

84. When the lift is moving upwards with some acceleration, the pressure exerted by a man is __________ to its acceleration.

A.Directly proportional

B.Inversely proportional

C.Cube root

D.None of these

Answer: A

85. Limiting force of friction is the

A.Tangent of angle between normal reaction and the resultant of normal reaction and limiting friction

B.Ratio of limiting friction and normal reaction

C.The friction force acting when the body is just about to move

D.The friction force acting when the body is in motion

Answer: C

86. A spherical body is symmetrical about its perpendicular axis. According to Routh’s rule, the moment of inertia of a body about an axis passing through its centre of gravity is (where, M = Mass of the body, and S = Sum of the squares of the two semi-axes.)

A.MS/3

B.MS/4

C.MS/5

D.None of these

Answer: C

87. The resultant of the following three couples 20 kg force, 0.5 m arm, +ve sense 30 kg force, 1 m arm, -ve sense 40 kg force, 0.25 m arm, +ve sense having arm of 0.5 m will be

A.20 kg, -ve sense

B.20 kg, + ve sense

C.10 kg, + ve sense

D.10 kg, -ve sense

Answer: A

88. In a framed structure, as shown in the below figure, the force in the member BC is

A.W/√3 (compression)

B.W/√3 (tension)

C.2W/√3 (compression)

D.2W/√3 (tension)

Answer: D

89. For any system of coplanar forces, the condition of equilibrium is that the

A.Algebraic sum of the horizontal components of all the forces should be zero

B.Algebraic sum of the vertical components of all the forces should be zero

C.Algebraic sum of moments of all the forces about any point should be zero

D.All of the above

Answer: D

90. D’ Alembert’s principle is used for

A.Reducing the problem of kinetics to equivalent statics problem

B.Determining stresses in the truss

C.Stability of floating bodies

D.Designing safe structures

Answer: A

91. Two bodies of masses m1 and m2 are hung from the ends of a rope, passing over a frictionless pulley as shown in the figure below. The acceleration of the string will be

A.g (m1 – m2)/(m1 + m2)

B.2g (m1 – m2)/(m1 + m2)

C.g (m1 + m2)/(m1 – m2)

D.2g (m1 + m2)/(m1 – m2)

Answer: A

92. The velocity ratio of a differential wheel and axle with ‘D’ as the diameter of effort wheel and d1 and d2 as the diameters of larger and smaller axles respectively, is

A.D/(d₁ + d₂)

B.D/(d₁ – d₂)

C.2D/(d₁ + d₂)

D.2D/(d₁ – d₂)

Answer: D

93. Which of the following is not the unit of power?

A.kW (kilowatt)

B.hp (horse power)

C.kcal/sec

D.kcal/kg sec

Answer: D

94. Non-coplanar non-concurrent forces are those forces which

A.Meet at one point, but their lines of action do not lie on the same plane

B.Do not meet at one point and their lines of action do not lie on the same plane

C.Do not meet at one point but their lines of action lie on the same plane

D.None of the above

Answer: B

95. The unit of force in S.I. units is

A.kilogram

B.Newton

C.Watt

D.Dyne

Answer: B

96. A number of forces acting at a point will be in equilibrium, if

A.All the forces are equally inclined

B.Sum of all the forces is zero

C.Sum of resolved parts in the vertical direction is zero (i.e. ∑V = 0)

D.None of these

Answer: C

97. The weight of a body is due to

A.Gravitational pull exerted by the earth

B.Forces experienced by body in atmosphere

C.Force of attraction experienced by particles

D.Gravitational force of attraction towards the centre of the earth

Answer: D

98. The efficiency of a lifting machine is the ratio of

A.Output to the input

B.Work done by the machine to the work done on the machine

C.Mechanical advantage to the velocity ratio

D.All of the above

Answer: D

99. According to principle of moments

A. If a system of coplanar forces is in equilibrium, then their algebraic sum is zero

B. If a system of coplanar forces is in equilibrium, then the algebraic sum of their moments about any point in their plane is zero

C. The algebraic sum of the moments of any two forces about any point is equal to moment of the resultant about the same point

D. Positive and negative couples can be balanced

Answer: B

100. Moment of inertia of a triangular section of baseB.and height (h) about an axis passing through its vertex and parallel to the base, is __________ than that passing through its C.G. and parallel to the base.

A.Nine times

B.Six times

C.Four times

D.Two times

Answer: A

101. A trolley wire weighs 1.2 kg per meter length. The ends of the wire are attached to two poles 20 meters apart. If the horizontal tension is 1500 kg find the dip in the middle of the span

A.2.5 cm

B.3.0 cm

C.4.0 cm

D.5.0 cm

Answer: C

102. The algebraic sum of the resolved parts of a number of forces in a given direction is equal to the resolved part of their resultant in the same direction. This is known as

A.Principle of independence of forces

B.Principle of resolution of forces

C.Principle of transmissibility of forces

D.None of these

Answer: B

103. A particle moves along a straight line such that distance (x) traversed in ‘t’ seconds is given by x = t² (t – 4), the acceleration of the particle will be given by the equation

A.6t² – 8t

B.3t² + 2t

C.6f – 8

D.6f – 4

Answer: C

104. The minimum force required to slide a body of weight ‘W’ on a rough horizontal plane is

A.W sinθ

B.W cosθ

C.W tanθ

D.None of these

Answer: C

105. The maximum frictional force which comes into play when a body just begins to slide over another surface is called

A.Limiting friction

B.Sliding friction

C.Rolling friction

D.Kinematic friction

Answer: A

106. The motion of a particle round a fixed axis is

A.Translatory

B.Rotary

C.Circular

D.Translatory as well as rotary

Answer: C

107. The C.G. of a right circular solid cone of height h lies at the following distance from the base

A.h/2

B.J/3

C.h/6

D.h/4

Answer: D

108. Which of the following statement is correct?

A.The kinetic energy of a body during impact remains constant

B.The kinetic energy of a body before impact is equal to the kinetic energy of a body after impact

C.The kinetic energy of a body before impact is less than the kinetic energy of a body after impact

D.The kinetic energy of a body before impact is more than the kinetic energy of a body after impact

Answer: D

109. A pair of smith’s tongs is an example of the lever of

A.Zeroth order

B.First order

C.Second order

D.Third order

Answer: C

110. Moment of inertia of a circular section about its diameterD.is

A.πd3/16

B.πd3/32

C.πd4/32

D.πd4/64

Answer: D

111. The forces, which meet at one point, but their lines of action do not lie in a plane, are called

A.Coplanar non-concurrent forces

B.Non-coplanar concurrent forces

C.Non-coplanar non-concurrent forces

D.Intersecting forces

Answer: B

112. The resultant of two forces P and Q acting at an angle θ is

A.√(P² + Q² + 2PQ sinθ)

B.√(P² + Q² + 2PQ cosθ)

C.√(P² + Q² – 2PQ cosθ)

D.√(P² + Q² – 2PQ tanθ)

Answer: B

113. Center of percussion is

A.The point of C.G.

B.The point of metacenter

C.The point of application of the resultant of all the forces tending to cause a body to rotate about a certain axis

D.Point of suspension

Answer: C

114. The static friction

A.Bears a constant ratio to the normal reaction between the two surfaces

B.Is independent of the area of contact, between the two surfaces

C.Always acts in a direction, opposite to that in which the body tends to move

D.All of the above

Answer: D

115. Least force required to draw a body up the inclined plane is W sin (plane inclination + friction angle) applied in the direction

A.Along the plane

B.Horizontally

C.Vertically

D.At an angle equal to the angle of friction to the inclined plane

Answer: D

116. The law of motion involved in the recoil of gun is

A.Newton’s first law of motion

B.Newton’s second law of motion

C.Newton’s third law of motion

D.None of these

Answer: C

117. A circular hole of 50 mm diameter is cut out from a circular disc of 100 mm diameter as shown in the below figure. The center of gravity of the section will lie

A.In the shaded area

B.In the hole

C.At ‘O’

D.None of these

Answer: A

118. A semicircular disc rests on a horizontal surface with its top flat surface horizontal and circular portion touching down. The coefficient of friction between semi circular disc and horizontal surface is µ. This disc is to be pulled by a horizontal force applied at one edge and it always remains horizontal. When the disc is about to start moving, its top horizontal force will

A.Remain horizontal

B.Slant up towards direction of pull

C.Slant down towards direction of pull

D.None of the above

Answer: C

119. Which of the following statement is correct?

A.The periodic time of a particle moving with simple harmonic motion is the time taken by a particle for one complete oscillation

B.The periodic time of a particle moving with simple harmonic motion is directly proportional to its angular velocity

C.The velocity of the particle moving with simple harmonic motion is zero at the mean position

D.The acceleration of the particle moving with simple harmonic motion is maximum at the mean position

Answer: A

120. In ideal machines

A.Mechanical advantage is greater than velocity ratio

B.Mechanical advantage is equal to velocity ratio

C.Mechanical advantage is less than velocity ratio

D.Mechanical advantage is unity

Answer: B

121. The forces, whose lines of action are parallel to each other and act in the same directions, are known as

A.Coplanar concurrent forces

B.Coplanar non-concurrent forces

C.Like parallel forces

D.Unlike parallel forces

Answer: C

122. Two non-collinear parallel equal forces acting in opposite direction

A.Balance each other

B.Constitute a moment

C.Constitute a couple

D.Constitute a moment of couple

Answer: C

123. If the body falls freely under gravity, then the gravitational acceleration is taken as

A.+8.9 m/s2

B.-8.9 m/s2

C.+9.8 m/s2

D.-9.8 m/s2

Answer: C

124. The center of gravity of a triangle lies at the point of

A.Concurrence of the medians

B.Intersection of its altitudes

C.Intersection of bisector of angles

D.Intersection of diagonals

Answer: A

125. One joule means that

A.Work is done by a force of 1 N when it displaces a body through 1 m

B.Work is done by a force of 1 kg when it displaces a body through 1 m

C.Work is done by a force of 1 dyne when it displaces a body through 1 cm

D.Work is done by a force of 1 g when it displaces a body through 1 cm

Answer: A

126. On the ladder resting on the ground and leaning against a smooth vertical wall, the force of friction will be

A.Downwards at its upper end

B.Upwards at its upper end

C.Perpendicular to the wall at its upper end

D.Zero at its upper end

Answer: D

127. Which of the following are vector quantities?

A.Angular displacement

B.Angular velocity

C.Angular acceleration

D.All of these

Answer: D

128. Which of the following is the locus of a point that moves in such a manner that its distance from a fixed point is equal to its distance from a fixed line multiplied by a constant greater than one

A.Ellipse

B.Hyperbola

C.Parabola

D.Circle

Answer: B

129. In a framed structure, as shown in the below figure, the forces in the members AB and BC are respectively

A.√3. W (tensile) and 2W (compressive)

B.2W (tensile) and √3. W (compressive)

C.2√3. W (tensile) and 2√3. W (compressive)

D.None of the above

Answer: A

130. When a body of mass ‘m’ attains a velocity ‘v’ from rest in time ‘t’, then the kinetic energy of translation is

A.mv2

B.mgv2

C.0.5 mv2

D.0.5 mgv2

Answer: C

131. The M.I. of hollow circular section about a central axis perpendicular to section as compared to its M.I. about horizontal axis is

A.Same

B.Double

C.Half

D.Four times

Answer: B

132. The maximum efficiency of a lifting machine is

A.1/m

B.V.R./m

C.m/V.R.

D.1/(m × V.R.)

Answer: D

133. When trying to turn a key into a lock, following is applied

A.Coplanar force

B.Non-coplanar forces

C.Moment

D.Couple

Answer: D

134. Moment of inertia of a triangular section of baseB.and height (h) about an axis passing through its C.G. and parallel to the base, is

A.bh3/4

B.bh3/8

C.bh3/12

D.bh3/36

Answer: D

135. If a number of forces act simultaneously on a particle, it is possible

A.Not a replace them by a single force

B.To replace them by a single force

C.To replace them by a single force through C.G.

D.To replace them by a couple

Answer: B

136. If two bodies having masses m1 and m2 (m1>m2) have equal kinetic energies, the momentum of body having mass m1 is _________ the momentum of body having mass m2.

A.Equal to

B.Less than

C.Greater than

D.None of these

Answer: C

137. Two coplanar couples having equal and opposite moments

A.Balance each other

B.Produce a couple and an unbalanced force

C.Are equivalent

D.Cannot balance each other

Answer: D

138. The center of gravity of a trapezium with parallel sides ‘a’ and ‘b’ lies at a distance of ‘y’ from the base ‘b’, as shown in the below figure. The value of ‘y’ is

A.h [(2a + b)/(a + b)]

B.(h/2) [(2a + b)/(a + b)]

C.(h/3) [(2a + b)/(a + b)]

D.(h/3) [(a + b)/(2a + b)]

Answer: C

139. Non-coplanar concurrent forces are those forces which

A.Meet at one point, but their lines of action do not lie on the same plane

B.Do not meet at one point and their lines of action do not lie on the same plane

C.Meet at one point and their lines of action also lie on the same plane

D.Do not meet at one point, but their lines of action lie on the same plane

Answer: A

140. In the equation of virtual work, following force is neglected

A.Reaction of any smooth surface with which the body is in contact

B.Reaction of a rough surface of a body which rolls on it without slipping

C.Reaction at a point or an axis, fixed in space, around which a body is constrained to turn

D.All of the above

Answer: D

141. The velocity of a particle moving with simple harmonic motion is _________ at the mean position.

A.Zero

B.Minimum

C.Maximum

D.None of these

Answer: C

142. If rain is falling in the opposite direction of the movement of a pedestrian, he has to hold his umbrella

A.More inclined when moving

B.Less inclined when moving

C.More inclined when standing

D.Less inclined when standing

Answer: D

143. The linear velocity of a body rotating at ω rad/s along a circular path of radius r is given by

A.ω/r

B.ω.r

C.ω2/r

D.ω2.r

Answer: B

144. The C.G. of a solid hemisphere lies on the central radius 3r

A.At distance — from the plane base 3r

B.At distance — from the plane base 3r

C.At distance — from the plane base 3r

D.At distance — from the plane base

Answer: D

145. The velocity ratio of a simple wheel and axle with D and d as the diameters of effort wheel and load axle, is

A.D + d

B.D – d

C.D × d

D.D / d

Answer: D

146. According to law of triangle of forces

A.Three forces acting at a point will be in equilibrium

B.Three forces acting at a point can be represented by a triangle, each side being proportional to force

C.If three forces acting upon a particle are represented in magnitude and direction by the sides of a triangle, taken in order, they will be in equilibrium

D.If three forces acting at a point are in equilibrium, each force is proportional to the sine of the angle between the other two

Answer: C

147. The loss of kinetic energy during inelastic impact, is given by (where m1 = Mass of the first body,m2 = Mass of the second body, and u1 and u2 = Velocities of the first and second bodies respectively.)

A.[m₁ m₂/2(m₁ + m₂)] (u₁ – u₂)²

B.[2(m₁ + m₂)/m₁ m₂] (u₁ – u₂)²

C.[m₁ m₂/2(m₁ + m₂)] (u₁² – u₂²)

D.[2(m₁ + m₂)/m₁ m₂] (u₁² – u₂²)

Answer: A

148. If a suspended body is struck at the center of percussion, then the pressure on die axis passing through the point of suspension will be

A.Maximum

B.Minimum

C.Zero

D.Infinity

Answer: C

149. A couple produces

A.Translatory motion

B.Rotational motion

C.Combined translatory and rotational motion

D.None of the above

Answer: B

150. The resolved part of the resultant of two forces inclined at an angle ‘θ’ in a given direction is equal to

A.The algebraic sum of the resolved parts of the forces in the given direction

B.The sum of the resolved parts of the forces in the given direction

C.The difference of the forces multiplied by the cosine of θ

D.The sum of the forces multiplied by the sine of θ

Answer: A

151. The force, by which the body is attracted, towards the center of the earth, is called

A.Impulsive force

B.Mass

C.Weight

D.Momentum

Answer: C

152. The equivalent length of a simple pendulum which gives the same frequency as compound pendulum is

A.h/(kG² + h²)

B.(kG² + h²)/h

C.h²/(kG² + h²)

D.(kG² + h²)/h²

Answer: B

153. Moment of inertia of a rectangular section having widthB.and depthD.about an axis passing through its C.G. and parallel to the width (b), is

A.db³/12

B.bd³/12

C.db³/36

D.bd³/36

Answer: B

154. The length of a second’s pendulum is

A.94.9 cm

B.99.4 cm

C.100 cm

D.101 cm

Answer: B

155. The angle between two forces when the resultant is maximum and minimum respectively are

A.0° and 180°

B.180° and 0°

C.90° and 180°

D.90° and 0°

Answer: A

156. The velocity ratio of a first system of pulleys with 4 pulleys is

A.4

B.8

C.16

D.20

Answer: C

157. Which of the following is a scalar quantity?

A.Force

B.Speed

C.Velocity

D.Acceleration

Answer: B

158. The unit of angular velocity is

A.m/min

B.rad/s

C.Revolutions/min

D.BothB.and (C)

Answer: D

159. The force required to move the body up the plane will be minimum if it makes an angle with the inclined plane __________ the angle of friction.

A.Equal to

B.Less than

C.Greater than

D.None of these

Answer: A

160. When a person, on a bicycle, drives round a curve, he has to lean __________ to maintain equilibrium.

A.Inward

B.Outward

C.Towards front

D.Towards back

Answer: A

161. The force induced in the string BC due to the load ‘W’ as shown in the below figure is

A.W sinθ

B.W cosθ

C.W tanθ

D.W cotθ

Answer: D

162. The center of gravity of a semi-circle lies at a distance of __________ from its base measured along the vertical radius.

A.3r/ 8

B.4r/ 3π

C.8r/3

D.3r/4π

Answer: B

163. The rate of doing work is known as

A.Potential energy

B.Kinetic energy

C.Power

D.None of these

Answer: C

164. The impact between two lead spheres is approximately equal to an __________ impact.

A.Elastic

B.Inelastic

C.Solid

D.None of these

Answer: B

165. The unit of angular acceleration is

A.N-m

B.m/s

C.m/s2

D.rad/s2

Answer: D

166. Which one of the following statements is not correct?

A.The tangent of the angle of friction is equal to coefficient of friction

B.The angle of repose is equal to angle of friction

C.The tangent of the angle of repose is equal to coefficient of friction

D.The sine of the angle of repose is equal to coefficient to friction

Answer: D

167. Coplanar concurrent forces are those forces which

A.Meet at one point, but their lines of action do not lie on the same plane

B.Do not meet at one point and their lines of action do not lie on the same plane

C.Meet at one point and their lines of action also lie on the same plane

D.Do not meet at one point, but their lines of action lie on the same plane

Answer: C

168. If ‘P’ is the force acting on the body, ‘m’ is the mass of the body and ‘a’ is the acceleration of the body, then according to Newton’s second law of motion,

A.P + m.a = 0

B.P – m.a = 0

C.P × m.a = 0

D.P/m.a = 0

Answer: B

169. If three forces acting in different planes can be represented by a triangle, these will be in

A.Non-equilibrium

B.Partial equilibrium

C.Full equilibrium

D.Unpredictable

Answer: A

170. The horizontal range of a projectile (R) is given by

A.R = u² cos2α/g

B.R = u² sin2α/g

C.R = u² cosα/g

D.R = u² sinα/g

Answer: B

171. A block of mass 20 kg lying on a rough horizontal plane is connected by a light string passing over a smooth pulley to another mass 5 kg, which can move freely in the Vertical direction, as shown in the below figure. The tension in the string will ___________ with the increase in coefficient of friction.

A.Increase

B.Decrease

C.Not be effected

D.None of these

Answer: A

172. Coplanar non-concurrent forces are those forces which __________ at one point, but their lines of action lie on the same plane.

A.Meet

B.Do not meet

C.Either ‘A’ or ‘B’

D.None of these

Answer: B

173. Which of the following do not have identical dimensions?

A.Momentum and impulse

B.Torque and energy

C.Torque and work

D.Moment of a force and angular momentum

Answer: D

174. In order to determine the effects of a force, acting on a body, we must know

A.Magnitude of the force

B.Line of action of the force

C.Nature of the force i.e. whether the force is push or pull

D.All of the above

Answer: D

175. A framed structure is perfect, if the number of members are __________ (2j – 3), where j is the number of joints.

A.Equal to

B.Less than

C.Greater than

D.None of these

Answer: A

176. The ratio of limiting friction and normal reaction is known as

A.Coefficient of friction

B.Angle of friction

C.Angle of repose

D.Sliding friction

Answer: A

177. The bodies which rebound after impact are called

A.Inelastic bodies

B.Elastic bodies

C.Neither elastic nor inelastic bodies

D.None of these

Answer: B

178. The velocity of a particle (v) moving with simple harmonic motion, at any instant is given by (where, r = Amplitude of motion, and y = Displacement of the particle from mean position.)

A.ω.√(y² – r²)

B.ω.√(r² – y²)

C.ω².√(y² – r²)

D.ω².√(r² – y²)

Answer: B

179. If n = number of members and y = number of joints, then for a perfect frame, n = ?

A.1/2

B.2/3

C.3/2

D.2/4

Answer: B

180. A framed structure is imperfect, if the numbers of members are __________ (2j – 3).

A.Equal to

B.Less than

C.Greater than

D.EitherB.or (C)

Answer: D

181. The time of flight (t) of a projectile on a horizontal plane is given by

A.t = 2u. sinα/g

B.t = 2u. cosα/g

C.t = 2u. tanα/g

D.t = 2u/g.sinα

Answer: A

182. Which of the following is not the unit of distance?

A.Angstrom

B.Light year

C.Micron

D.Milestone

Answer: D

183. Two like parallel forces are acting at a distance of 24 mm apart and their resultant is 20 N. It the line of action of the resultant is 6 mm from any given force, the two forces are

A.15 N and 5 N

B.20 N and 5 N

C.15 N and 15 N

D.None of these

Answer: A

184. Which of the following are vector quantities?

A.Linear displacement

B.Linear velocity

C.Linear acceleration

D.All of these

Answer: D

185. Varingon’s theorem of moments states that if a number of coplanar forces acting on a particle are in equilibrium, then

A.Their algebraic sum is zero

B.Their lines of action are at equal distances

C.The algebraic sum of their moments about any point in their plane is zero

D.The algebraic sum of their moments about any point is equal to the moment of their resultant force about the same point

Answer: D

186. The possible loading in various members of framed structures are

A.Compression or tension

B.Buckling or shear

C.Shear or tension

D.All of the above

Answer: A

187. The acceleration of a particle moving with simple harmonic motion is __________ at the mean position.

A.Zero

B.Minimum

C.Maximum

D.None of these

Answer: A

188. Efficiency of a screw jack is given by (where α = Helix angle, and φ = Angle of friction.)

A.tan(α + φ)/tanα

B.tanα/tan (α + φ)

C.tan(α – φ)/tanα

D.None of these

Answer: B

189. The force induced in the string AB due to the load W, as shown in the below figure is

A.W sinθ

B.W cosθ

C.W secθ

D.W cosecθ

Answer: D

190. The unit of work or energy in S.I. units is

A.Newton

B.Pascal

C.Watt

D.Joule

Answer: D

191. The velocity ratio for the first system of pulleys is (where n is the number of pulleys.)

A.n

B.n²

C.2n

D.2n – 1

Answer: C

192. If a number of coplanar forces acting at a point be in equilibrium, the sum of clockwise moments must be __________ the sum of anticlockwise moments, about any point.

A.Equal to

B.Less than

C.Greater than

D.None of these

Answer: A

193. Center of gravity of a thin hollow cone lies on the axis at a height of

A.One-fourth of the total height above base

B.One-third of the total height above base

C.One-half of the total height above base

D.Three-eighth of the total height above the base

Answer: B

194. Which of the following statement is correct in connection with projectiles?

A.A path, traced by a projectile in the space, is known as trajectory.

B.The velocity, with which a projectile is projected, is known as the velocity of projection.

C.The angle, with the horizontal, at which a projectile is projected, is known as angle of projection.

D.All of the above

Answer: D

195. A pendulum which executes one beat per second is known as

A.Simple pendulum

B.Compound pendulum

C.Torsional pendulum

D.Second’s pendulum

Answer: D

196. A single force and a couple acting in the same plane upon a rigid body

A.Balance each other

B.Cannot balance each other

C.Produce moment of a couple

D.Are equivalent

Answer: B

197. The forces which meet at one point, but their lines of action __________ on the same plane, are Known as non-coplanar concurrent forces.

A.Lie

B.Do not lie

C.Either A or B

D.None of these

Answer: B

198. During elastic impact, the relative velocity of the two bodies after impact is __________ the relative velocity of the two bodies before impact.

A.Equal to

B.Equal and opposite to

C.Less than

D.Greater than

Answer: D

199. A force is completely defined when we specify

A.Magnitude

B.Direction

C.Point of application

D.All of the above

Answer: D

200. The rate of change of momentum is directly proportional to the impressed force, and takes place in the same direction in which the force acts. This statement is known as

A.Newton’s first law of motion

B.Newton’s second law of motion

C.Newton’s third law of motion

D.None of these

Answer: B

201. The maximum efficiency of a screw jack is

A.(1 – sinφ)/(1 + sinφ)

B.(1 + sinφ)/(1 – sinφ)

C.(1 – tanφ)/(1 + tanφ)

D.(1 + tanφ)/(1 – tanφ)

Answer: A

202. The center of percussion of a solid cylinder of radius ‘r’ resting on a horizontal plane will be

A.r/2

B.2r/3

C.r/A

D.3r/2

Answer: D

203. The velocity ratio of a differential pulley block with D and d as the diameters of larger and smaller pulley, is

A.D/(D – d)

B.D/(D + d)

C.2D/(D – d)

D.2D/(D + d)

Answer: C

204. In a screw jack, the effort required to lower the load is __________ the effort required to raise the same load.

A.Less than

B.Equal to

C.More than

D.None of these

Answer: A

205. Tangent of angle of friction is equal to

A.Kinetic friction

B.Limiting friction

C.Angle of repose

D.Coefficient of friction

Answer: D

206. For a self locking machine, the efficiency must be

A.Equal to 50%

B.Less than 50%

C.Greater than 50%

D.100%

Answer: B

207. If the number of pulleys in a system is equal to its velocity ratio, then it is a __________ system of pulleys.

A.First

B.Second

C.Third

D.None of these

Answer: B

208. Effect of a force on a body depends upon

A.Magnitude

B.Direction

C.Position or line of action

D.All of the above

Answer: D

209. The ideal angle of banking provided on the curves on roads depends upon

A.Weight of the vehicle

B.(Velocity)2 of the vehicle

C.Nature of the road surface

D.Coefficient of friction between the road and vehicle contact point

Answer: B

210. Two blocks ‘A’ and ‘B’ of masses 150 kg and 50 kg respectively are connected by means of a string as shown in the below figure. The tension in all the three strings __________ be same.

A.Will

B.Will not

C.Either A or B

D.None of these

Answer: Option

211. The bellow figure shows the two equal forces at right angles acting at a point. The value of force ‘R’ acting along their bisector and in opposite direction is

A.P/2

B.2P

C.√2 × P

D.P/√2

Answer: C

212. A lead ball with a certain velocity is made to strike a wall, it falls down, but rubber ball of same mass and with same velocity strikes the same wall, it rebounds. Select the correct reason from the following:

A.Both the balls undergo an equal change in momentum

B.The change in momentum suffered by rubber ball is more than the lead ball

C.The change in momentum suffered by rubber ball is less than the lead ball

D.None of the above

Answer: B

213. In order to completely specify angular displacement by a vector, it must fix

A.Direction of the axis of rotation

B.Magnitude of angular displacement

C.Sense of angular displacement

D.All of these

Answer: D

214. The moment of inertia of a rectangular section 3 cm wide and 4 cm deep about X-X axis is

A.9 cm4

B.12 cm4

C.16 cm4

D.20 cm4

Answer: C

215. A framed structure is perfect if it contains members equal to
(Where, n = number of joints in a frame)

A.2n³

B.2n

C.n²

D.3n²

Answer: A

216. The motion of a wheel of a car is

A.Purely translation

B.Purely rotational

C.Combined translation and rotational

D.None of these

Answer: C

217. A smooth cylinder lying on its convex surface remains in __________ equilibrium.

A.Stable

B.Unstable

C.Neutral

D.None of these

Answer: B

218. The velocity ratio in case of an inclined plane inclined at angle ‘θ’ to the horizontal and weight being pulled up the inclined plane by vertical effort is

A.sinθ

B.cosθ

C.tanθ

D.cosecθ

Answer: A

219. Forces are called concurrent when their lines of action meet in

A.One point

B.Two points

C.Plane

D.Perpendicular planes

Answer: A

220. The range of a projectile is maximum, when the angle of projection is

A.30°

B.45°

C.60°

D.90°

Answer: B

221. When a rigid body is suspended vertically, and it oscillates with a small amplitude under the action of the force of gravity, the body is known as

A.Simple pendulum

B.Compound pendulum

C.Torsional pendulum

D.Second’s pendulum

Answer: B

222. The potential energy of a vertically raised body is __________ the kinetic energy of a vertically falling body.

A.Equal to

B.Less than

C.Greater than

D.None of these

Answer: A

223. The acceleration of a particle moving with simple harmonic motion, at any instant is given by

A.ω.y

B.ω2.y

C.ω2/y

D.ω3.y

Answer: B

224. The units of moment of inertia of mass are

A.kg-m²

B.m²/kg

C.kg/m²

D.kg/m

Answer: A

225. The linear acceleration A. of a body rotating along a circular path of radius (r) with an angular acceleration of α rad/s2, is

A.a = α/ r

B.a = α.r

C.a = r / α

D.None of these

Answer: B

226. Whenever a force acts on a body and the body undergoes a displacement, then

A.Work is said to be done

B.Power is being transmitted

C.Body has kinetic energy of translation

D.None of these

Answer: A

227. Which of the following is not the unit of energy?

A.kg m

B.kcal

C.Watt

D.Watt hours

Answer: C

228. The range of projectile will be maximum for a given velocity of projectile, when the angle of projection (α) is

A.β/2

B.30° + β/2

C.45° + β/2

D.60° + β/2

Answer: C

229. The power developed by a body acted upon by a torque ‘T’ Newton meter (N – m) and revolving at ω radian/s is given by

A.T.ω (in watts)

B.T.ω/60 (in watts)

C.T.ω/75 (in kilowatts)

D.T.ω/4500 (in kilowatts)

Answer: A

230. According to Lami’s theorem

A.The three forces must be equal

B.The three forces must be at 120° to each other

C.The three forces must be in equilibrium

D.If the three forces acting at a point are in equilibrium, then each force is proportional to the sine of the angle between the other two

Answer: D

231. Which of the following is not the unit of work, energy and heat?

A.kcal

B.kg-m

C.kW-hr

D.h.p

Answer: D

232. If the masses of both the bodies, as shown in the below figure, are doubled, then the acceleration in the string will be

A.Same

B.Half

C.Double

D.None of these

Answer: A

233. If a body is acted upon by a number of coplanar non-concurrent forces, it may

A.Rotate about itself without moving

B.Move in any one direction rotating about itself

C.Be completely at rest

D.All of these

Answer: D

234. The moment of inertia of a square of sideA.about an axis through its center of gravity is

A.a4/4

B.a4/8

C.a4/12

D.a4/36

Answer: C

235. A projectile is fired at an angle ‘θ’ to the vertical. Its horizontal range will be maximum when ‘θ’ is

A.0°

B.30°

C.45°

D.60°

Answer: C

236. The time of flight of a projectile on downward inclined plane depends upon

A.Angle of projection

B.Angle of inclination of the plane

C.BothA.and (B)

D.None of these

Answer: C

237. Which of the following is not a scalar quantity?

A.Mass

B.Volume

C.Density

D.Acceleration

Answer: D

238. The overturning of a vehicle on a level circular path can be avoided if the velocity of vehicle is __________ √(gra/h)

A.Less than

B.Greater than

C.Equal to

D.None of these

Answer: A

239. According to the law of moments, if a number of coplanar forces acting on a particle are in equilibrium, then

A.Their algebraic sum is zero

B.Their lines of action are at equal distances

C.The algebraic sum of their moments about any point in their plane is zero

D.The algebraic sum of their moments about any point is equal to the moment of their resultant force about the same point

Answer: C

240. When the spring of a watch is wound, it will possess

A.Strain energy

B.Kinetic energy

C.Heat energy

D.Electrical energy

Answer: A

241. The velocity ratio for the third system of pulleys is

A.n

B.n²

C.2n

D.2n – 1

Answer: D

242. Dynamic friction as compared to static friction is

A.Same

B.More

C.Less

D.May be less of more depending on nature of surfaces and velocity

Answer: C

243. Mass moment of inertia of a thin rod about its one end is ___________ the mass moment of inertia of the same rod about its mid-point

A.Same as

B.Twice

C.Thrice

D.Four times

Answer: D

244. In the shown figure, if the angle of inclination of the plane is increased, then acceleration of the system will

A.Increase

B.Decrease

C.Remain the same

D.None of these

Answer: B

245. An ideal machine is one whose efficiency is

A.Between 60 and 70 %

B.Between 70 and 80%

C.Between 80 and 90%

D.100%

Answer: D

246. If a number of forces are acting at a point, their resultant is given by

A.(∑V)2 + (∑H)2

B.√[(∑V)2 + (∑H)2]

C.(∑V)2 +(∑H)2 +2(∑V)(∑H)

D.√[(∑V)2 +(∑H)2 +2(∑V)(∑H)]

Answer: B

247. The force applied on a body of mass 100 kg to produce an acceleration of 5 m/s2, is

A.20 N

B.100 N

C.500 N

D.None of these

Answer: C

248. Which of the following is not the unit of pressure?

A.kg/cm

B.Bar

C.Atmosphere

D.Newton

Answer: D

249. The maximum frictional force, which comes into play, when a body just begins to slide over the surface of the other body, is known as

A.Static friction

B.Dynamic friction

C.Limiting friction

D.Coefficient of friction

Answer: C

250. The principle of transmissibility of forces states that, when a force acts upon a body, its effect is

A.Same at every point on its line of action

B.Different at different points on its line of action

C.Minimum, if it acts at the center of gravity of the body

D.Maximum, if it acts at the center of gravity of the body

Answer: C

251. In a screw jack, the effort required to lift the load is given by (where W = Load lifted, α = Helix angle, and φ = Angle of friction.)

A.P = W tan (α – φ)

B.P = W tan (α + φ)

C.P = W tan (φ – α)

D.P = W cos (α + φ)

Answer: B 12.

252. The moment of inertia of a thin disc of mass ‘m’ and radius ‘r’, about an axis through its center of gravity and perpendicular to the plane of the disc is

A.mr2/2

B.mr2/4

C.mr2/6

D.mr2/8

Answer: A

253. If a rigid body is in equilibrium under the action of three forces, then

A.These forces are equal

B.The lines of action of these forces meet in a point

C.The lines of action of these forces are parallel

D.BothB.andC.above

Answer: D

254. The matter contained in a body, is called

A.Impulsive force

B.Mass

C.Weight

D.Momentum

Answer: B

255. Moment of inertia is the

A.Second moment of force

B.Second moment of area

C.Second moment of mass

D.All of these

Answer: D

256. Joule is the unit of

A.Force

B.Work

C.Power

D.Velocity

Answer: B

257. The coefficient of friction depends on

A.Area of contact

B.Shape of surfaces

C.Strength of surfaces

D.Nature of surface

Answer: D

258. In a framed structure, as shown in the below figure, the force in the member AB is __________ the force in member AC.

A.Half

B.Equal to

C.Double

D.None of these

Answer: A

259. The velocity ratio of a single purchase crab winch can be increased by

A.Increasing the length of the handle

B.Increasing the radius of the load drum

C.Increasing the number of teeth of the pinion

D.All of the above

Answer: A

260. Two balls of equal mass and of perfectly elastic material are lying on the floor. One of the balls with velocity ‘v’ is made to strike the second ball. Both the balls after impact will move with a velocity

A.v

B.v/2

C.v/4

D.v/8

Answer: B

261. Moment of inertia of a circular section about an axis perpendicular to the section is

A.πd3/16

B.πd3/32

C.πd4/32

D.πd4/64

Answer: C

262. A redundant frame is also called __________ frame.

A.Perfect

B.Imperfect

C.Deficient

D.None of these

Answer: B

263. Tension in the cable supporting a lift is more when the lift is moving __________ with an acceleration.

A.Upwards

B.Downwards

C.Horizontal

D.None of these

Answer: A

264. The unit of work in S.I. units is

A.Newton

B.erg

C.kg-m

D.joule

Answer: D

265. If the gravitational acceleration at any place is doubled, then the weight of a body will be

A.g/2

B.g

C.√2.g

D.2g

Answer: D

266. The moment of inertia of a sphere of mass ‘m’ and radius ‘r’, about an axis tangential to it, is

A.2mr2/3

B.2mr2/5

C.7mr2/3

D.7mr2/5

Answer: D

267. The center of gravity of a quadrant of a circle lies along its central radius (r) at a distance of

A.0.5 r

B.0.6 r

C.0.7 r

D.0.8 r

Answer: B

268. The unit of moment of inertia of an area is

A.kg-m2

B.kg-m-s2

C.kg/m2

D.m4

Answer: D

269. When a body of mass moment of inertia ‘I’ (about a given axis) is rotated about that axis with an angular velocity to, then the kinetic energy of rotation is

A.Iω

B.Iω2

C.0.5 Iω

D.0.5 Iω2

Answer: D

270. In a single threaded worm and worm wheel, the number of teeth on the worm is 50. The diameter of the effort wheel is 100 mm and that of load drum is 50 mm. The velocity ratio is

A.50

B.100

C.200

D.400

Answer: B

271. One joule is equal to

A.0.1 N-m

B.1 N-m

C.10 N-m

D.100 N-m

Answer: B

272. A differential pulley block has larger and smaller diameters of 100 mm and 80 mm respectively. Its velocity ratio is

A.5

B.10

C.20

D.40

Answer: B

273. A body will begin to move down an inclined plane if the angle of inclination of the plane is _________ the angle of friction.

A.Equal to

B.Less than

C.Greater than

D.None of these

Answer: C

274. The friction experienced by a body, when in motion, is known as

A.Rolling friction

B.Dynamic friction

C.Limiting friction

D.Static friction

Answer: B

275. Mass moment of inertia of a uniform thin rod of mass M and length (l) about its mid-point and perpendicular to its length is

A.(2/3) Ml²

B.(1/3) Ml²

C.(3/4) Ml²

D.(1/12) Ml²

Answer: D

276. If a given force (or a given system of forces) acting on a body __________ the position of the body, but keeps it in equilibrium, then its effect is to produce internal stress in the body.

A.Change

B.Does not change

C.Changes periodically

D.None of these

Answer: B

277. One end of a helical spring is fixed while the other end carries the load W which moves with simple harmonic motion. The frequency of motion is given by (where δ = Deflection of the spring.)

A.2π. √(g/δ)

B.1/2π. √(g/δ)

C.2π. √(δ/g)

D.1/2π. √(δ/g)

Answer: B

278. If tension in the cable supporting a lift moving downwards is half the tension when it is moving upwards, the acceleration of the lift is

A.g/2

B.g/3

C.g/4

D.None of these

Answer: D

279. The friction experienced by a body, when at rest, is known as

A.Static friction

B.Dynamic friction

C.Limiting friction

D.Coefficient of friction

Answer: A

280. The unit of force in S.I. system of units is

A.Dyne

B.Kilogram

C.Newton

D.Watt

Answer: C

281. One kg force is equal to

A.7.8 N

B.8.9 N

C.9.8 N

D.12 N

Answer: C

282. The resultant of the two forces ‘P’ and ‘Q’ is ‘R’. If ‘Q’ is doubled, the new resultant is perpendicular to ‘P’. Then

A.P = Q

B.Q = R

C.Q = 2R

D.None of these

Answer: B

283. The amplitude is always __________ radius of the circle.

A.Equal to

B.Less than

C.Greater than

D.None of these

Answer: A

284. The moment of the force ‘P’ about ‘O’ as shown in the below figure is

A.P × OA

B.P × OB

C.P × OC

D.P × AC

Answer: C

285. The process of finding out the resultant force is called __________ of forces.

A.Composition

B.Resolution

C.Decomposition

D.None of these

Answer: A

286. Which of the following is an equation of linear motion?(where, u and v = Initial and final velocity of the body, a = Acceleration of the body, and s = Displacement of the body in time t seconds.)

A.v = u + a.t

B.s = u.t + ½ a.t2

C.v2 = u2 + 2a.s

D.All of these

Answer: D

287. Moment of inertia of a hollow circular section, as shown in the below figure about X-axis, is

A.π/16 (D² – d²)

B.π/16 (D³ – d³)

C.π/32 (D⁴ – d⁴)

D.π/64 (D⁴ – d⁴)

Answer: D

288. The forces which do not meet at one point and their lines of action do not lie on the same plane are known as

A.Coplanar concurrent forces

B.Coplanar non-concurrent forces

C.Non-coplanar concurrent forces

D.None of these

Answer: D

289. Concurrent forces are those forces whose lines of action

A.Lie on the same line

B.Meet at one point

C.Meet on the same plane

D.None of these

Answer: B

290. The moment of inertia of a solid cylinder of mass ‘m’, radius ‘r’ and length ‘l’ about the longitudinal axis or polar axis is

A.mr2/2

B.mr2/4

C.mr2/6

D.mr2/8

Answer: A

291. According to parallel axis theorem, the moment of inertia of a section about an axis parallel to the axis through center of gravity (i.e. IP) is given by(where, A = Area of the section, IG = Moment of inertia of the section about an axis passing through its C.G., and h = Distance between C.G. and the parallel axis.)

A.IP = IG + Ah2

B.IP = IG – Ah2

C.IP = IG / Ah2

D.IP = Ah2 / IG

Answer: A

291. The law of the machine is (where P = Effort applied to lift the load, m = A constant which is equal to the slope of the line, W = Load lifted, and C = Another constant which represents the machine friction.)

A.P = mW – C

B.P = m/W + C

C.P = mW + C

D.P = C – mW

Answer: C

292. The wheels of a moving car possess

A.Potential energy only

B.Kinetic energy of translation only

C.Kinetic energy of rotation only

D.Kinetic energy of translation and rotation both

Answer: D

293. The resultant of two equal forces ‘P’ making an angle ‘θ’, is given by

A.2P sinθ/2

B.2P cosθ/2

C.2P tanθ/2

D.2P cotθ/2

Answer: B

294. The coefficient of restitution for inelastic bodies is

A.Zero

B.One

C.Between zero and one

D.More than one

Answer: A

295. If a number of forces are acting at a point, their resultant will be inclined at an angle ‘θ’ with the horizontal, such that

A.tanθ = ΣH/ΣV

B.tanθ = ΣV/ΣH

C.tanθ = ΣV × ΣH

D.tanθ = √(ΣV + ΣH)

Answer: B

296. The periodic time of a particle with simple harmonic motion is _________ proportional to the angular velocity.

A.Directly

B.Inversely

C.Square root

D.None of these

Answer: B

297. The efficiency of a screw jack is maximum, when (where α = Helix angle, and φ = Angle of friction.)

A.α = 45° + φ/2

B.α = 45° – φ/2

C.α = 90° + φ

D.α = 90° – φ

Answer: B

298. The total motion possessed by a body, is called

A.Impulsive force

B.Mass

C.Weight

D.Momentum

Answer: D
299. A screw jack used for lifting the loads is

A.A reversible machine

B.A non-reversible machine

C.An ideal machine

D.None of these

Answer: B

300. If u1 and u2 are the velocities of two moving bodies in the same direction before impact and v1 and v2 are their velocities after impact, then coefficient of restitution is given by

A.(v1 – v2)/(u1 – u2)

B.(v₂ – v₁)/(u1 – u2)

C.(u1 – u2)/(v1 – v2)

D.(u₂ + u₁)/(v₂ + v₁)

Answer: B

301. Work done is said to be zero, when

A.Some force acts on a body, but displacement is zero

B.No force acts on a body but some displacement takes place

C.EitherA.or (B)

D.None of the above

Answer: C

302. The range of projectile on a downward inclined plane is ________ the range on upward inclined plane for the same velocity of projection and angle of projection.

A.Less than

B.More than

C.Equal to

D.None of These

Answer: B

303. The point, through which the whole weight of the body acts, irrespective of its position, is known as

A.Moment of inertia

B.Center of gravity

C.Center of percussion

D.Center of mass

Answer: B

304. The total energy possessed by a system of moving bodies

A.Is constant at every instant

B.Varies from point to point

C.Is maximum in the start and minimum at the end

D.Is minimum in the start and maximum at the end

Answer: A

305. The acceleration of a body sliding down an inclined surface is

A.g sinθ

B.g cosθ

C.g tanθ

D.None of these

Answer: A

306. A force while acting on a body may

A.Change its motion

B.Balance the forces, already acting on it

C.Give rise to the internal stresses in it

D.All of these

Answer: D

307. A machine having an efficiency less than 50%, is known as

A.Reversible machine

B.Non-reversible machine

C.Neither reversible nor non-reversible machine

D.Ideal machine

Answer: B

308. Static friction is always __________ dynamic friction.

A.Equal to

B.Less than

C.Greater than

D.None of these

Answer: C

309. In the shown figure, the tension (T) in the string will be

A.m₁. m₂. g/(m₁ + m₂)

B.2m₁. m₂. g/(m₁ + m₂)

C.(m₁ + m₂)/ m₁. m₂. g

D.(m₁ + m₂)/2m₁. m₂. g

Answer: B

310. A body of weight ‘W’ is required to move up on rough inclined plane whose angle of inclination with the horizontal is ‘α’. The effort applied parallel to the plane is given by (where μ = tanφ = Coefficient of friction between the plane and the body.)

A.P = W tanα

B.P = W tan (α + φ)

C.P = W (sinα + μcosα)

D.P = W (cosα + μsinα)

Answer: C

311. A smooth cylinder lying on a __________ is in neutral equilibrium.

A.Curved surface

B.Convex surface

C.Horizontal surface

D.None of these

Answer: C

312. The unit of energy in S.I. units is

A.Dyne

B.Watt

C.kg-m

D.Joule

Answer: D

313. A ladder is resting on a rough ground and leaning against a smooth vertical wall. The force of friction will act

A.Downward at its upper end

B.Upward at its upper end

C.Zero at its upper end

D.Perpendicular to the wall at its upper end

Answer: C

314. The periodic time of one oscillation for a simple pendulum is (where l = Length of the pendulum.)

A.(1/2π). √(l/g)

B.(1/2π). √(g/l)

C.2π. √(l/g)

D.None of these

Answer: C

315. The total momentum of a system of masses (i. e. moving bodies) in any one direction remains constant, unless acted upon by an external force in that direction. This statement is called

A.Newton’s first law of motion

B.Newton’s second law of motion

C.Principle of conservation of energy

D.Principle of conservation of momentum

Answer: D

316. The moment of inertia of a thin spherical shell of mass m and radius r, about its diameter is

A.mr2/3

B.2mr2/3

C.2mr2/5

D.3mr2/5

Answer: B

317. The moment of inertia of a solid cone of mass ‘m’ and base radius ‘r’ about its vertical axis is

A.3mr2/5

B.3mr2/10

C.2mr2/5

D.4mr2/5

Answer: B

318. If the resultant of two equal forces has the same magnitude as either of the forces, then the angle between the two forces is

A.30°

B.60°

C.90°

D.120°

Answer: D

319. In actual machines, mechanical advantage is _________ velocity ratio.

A.Equal to

B.Less than

C.Greater than

D.None of these

Answer: B

320. The moment of inertia of a solid sphere of mass ‘m’ and radius ‘r’ is

A.2mr2/3

B.2mr2/5

C.mr2

D.mr2/2

Answer: B

321. Moment of inertia of a rectangular section having widthB.and depthD.about an axis passing through its C.G. and parallel to the depth (d), is

A.db³/12

B.bd³/12

C.db³/36

D.bd³/36

Answer: A

322. The unit of power in S.I. units is

A.Horsepower

B.Joule

C.Watt

D.kg-m

Answer: C

323. The maximum height of a projectile on a horizontal plane, is

A.u² sin²α/2g

B.u² cos²α/2g

C.u² sin²α/g

D.u² cos²α/g

Answer: A

324. One watt is equal to

A.0.1 joule/s

B.1 joule/s

C.10 joules/s

D.100 joules/s

Answer: B

325. The moment of inertia of a square of side a about its diagonal is

A.a2/8

B.a3/12

C.a4/12

D.a4/16

Answer: C

326. The maximum acceleration of a particle moving with simple harmonic motion is

A.ω

B.ωr

C.ω2r

D.ω/r

Answer: C

327. The rate of change of displacement of a body is called

A.Velocity

B.Acceleration

C.Momentum

D.None of these

Answer: A

328. The maximum mechanical advantage of a lifting machine is

A.1 + m

B.1 – m

C.1 / m

D.m

Answer: C

Engineering Mechanics Important Questions :-