Which is the correct statement about law of polygon of forces ? | ENGINEERING MECHANICS

(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
(e) none of the above.
Ans: d

According to principle of transmissibility of forces, the effect of a force upon a body is | ENGINEERING MECHANICS

(a) maximum when it acts at the center of gravity of a body
(b) different at different points in its line of action
(c) the same at every point in its line of action
(d) minimum when it acts at the C.G. of the body
(e) none of the above.
Ans: c

Center of gravity of a solid cone lies on the axis at the height | ENGINEERING MECHANICS

(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
(e) none of the above.
Ans: a

Center of percussion is | ENGINEERING MECHANICS

(a) the point of C.G.
(b) the point of metacentre
(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
(e) the point in a body about which it can rotate horizontally and oscillate under the influence of gravity.
Ans: c