Machine Dynamics Multiple Choice Questions on “Circular Arc Cam with Flatfaced Follower”.
1. When the flanks of the cam connecting the base circle and nose are of convex circular arcs, then the cam is known as _______
a) Circular frame cam
b) Tanget arc cam
c) Tangent frame
d) Circular arc cam
Answer: d
Clarification: When the flanks of the cam connecting the base circle and nose are of convex circular arcs, then the cam is known as Circular arc cam, there are no cams such as tangent frame, circular frame cams.
2. The size of cam is independent of the base circle.
a) True
b) False
Answer: b
Clarification: The size of cam is defined by the radius of the base circle which is also known as the smallest circle and is independent of the pitch circle.
3. On which of the following factors does the pressure angle of the cam does not depend?
a) Offset between centre lines of follower and cam
b) Angle of ascent
c) Lift of the follower
d) Shape of cam
Answer: d
Clarification: The pressure angle of the cam depends on the following factors”
offset between center lines of follower and cam, angle of ascent and lift of follower, it is independent of the shape of cam.
4. If φ is the angle of action of cam on the circular flank, and r1 is the base circle of the cam, then the maximum velocity of the follower is given by the equation.
a) ω(R-r1)sin φ
b) ω(R+r1)sin φ
c) ω(R-r1)cos φ
d) ω(R+r1)cos φ
Answer: a
Clarification: The velocity of the follower is dependent of the following factors:
base circle radius, rotation speed of the cam, angle of action of cam on the circular flank and Radius of circular flank.
5. If φ is the angle of action of cam on the circular flank, and r1 is the base circle of the cam, then the maximum acceleration of the follower is given by the equation.
a) ω2(R-r1)
b) ω2(R+r1)sin φ
c) ω2(R-r1)cos φ
d) ω2(R+r1)cos φ
Answer: a
Clarification: The maximum acceleration of the follower is dependent of the following factors: base circle radius, rotation speed of the cam and radius of circular flank.
6. If φ is the angle of action of cam on the circular flank, and r1 is the base circle of the cam, then the minimum acceleration of the follower is given by the equation.
a) ω2(R-r1)
b) ω2(R+r1)sin φ
c) ω2(R-r1)cos φ
d) ω2(R+r1)cos φ
Answer: c
Clarification: The minimum acceleration of the follower is dependent of the following factors:
base circle radius, rotation speed of the cam, cosine of angle of action of cam on the circular flank and radius of circular flank.
7. Flat faced follower’s acceleration when in contact with a circular arc cam is given by _________
a) ω2(R-r1)
b) ω2(R+r1)sin φ
c) ω2(R-r1)cos φ
d) ω2(R+r1)cos φ
Answer: c
Clarification: The acceleration of the follower is dependent of the following factors:
base circle radius, rotation speed of the cam, cosine of angle of action of cam on the circular flank and radius of circular flank.
8. The maximum acceleration of the follower occurs when the angle of action of cam on the circular flank is 90 degrees
a) True
b) False
Answer: b
Clarification: The acceleration of the follower is dependent of the following factors:
base circle radius, rotation speed of the cam, cosine of angle of action of cam on the circular flank and radius of circular flank. Since at φ = 90 degrees the cosine will become 0 and hence it will not be maximum.