Machine Dynamics Multiple Choice Questions on “Classification of Cams”.
1. Cam size depends upon
a) base circle
b) pitch circle
c) prime circle
d) outer circle
Answer: a
Clarification: Cam size depends upon base circle. The pressure angle of a cam depends upon offset between centre lines of cam and follower,lift of follower and angle of ascent.
2. Angle of ascent of cam is defined as the angle
a) during which the follower returns to its initial position
b) of rotation of the cam for a definite displacement of the follower
c) through which the cam rotates during the period in which the follower remains in highest position
d) moved by the cam from the instant the follower begins to rise, till it reaches its highest position
Answer: d
Clarification: Angle of ascent of cam is defined as the angle moved by the cam from the instant the follower begins to rise, till it reaches its highest position. Angle of action of cam is defined as the angle moved by the cam from beginning of ascent to the termination of descent.
3. The pressure angle of a cam depends upon
a) offset between centre lines of cam and follower
b) lift of follower
c) angle of ascent
d) all of the mentioned
Answer: d
Clarification: Cam size depends upon base circle. The pressure angle of a cam depends upon offset between centre lines of cam and follower,lift of follower and angle of ascent.
4. Angle of action of cam is defined as the angle
a) of rotation of the cam for a definite displacement of the follower
b) through which the cam rotates during the period in which the follower remains in the highest position
c) moved by the cam from the instant the follower begins to rise, till it reaches its highest position
d) moved by the cam from beginning of ascent to the termination of descent
Answer: d
Clarification: Angle of ascent of cam is defined as the angle moved by the cam from the instant the follower begins to rise, till it reaches its highest position. Angle of action of cam is defined as the angle moved by the cam from beginning of ascent to the termination of descent.
5. Throw of a cam is the maximum distance of the follower from
a) base circle
b) pitch circle
c) root circle
d) prime circle
Answer: a
Clarification: Cam size depends upon base circle. Throw of a cam is the maximum distance of the follower from base circle.
6. Cylindrical cams can be classified as
a) circular
b) tangent
c) reciprocating
d) none of the mentioned
Answer: d
Clarification: A cylindrical cam or barrel cam is a cam in which the follower rides on the surface of a cylinder. In the most common type, the follower rides in a groove cut into the surface of a cylinder. These cams are principally used to convert rotational motion to linear motion parallel to the rotational axis of the cylinder. A cylinder may have several grooves cut into the surface and drive several followers.
7. The cam follower generally used in aircraft engines is
a) knife edge follower
b) flat faced follower
c) spherical faced follower
d) roller follower
Answer: d
Clarification: The roller followers are extensively used where more space is available such as in stationary gas and oil engines and aircraft engines.
8. For S.H.M. cam, the acceleration of the follower at the ends of the stroke and aimed stroke respectively, is
a) maximum and zero
b) zero and maximum
c) minimum and maximum
d) zero and minimum