Machine Kinematics Multiple Choice Questions on “Types of Friction”.
1. _____________ friction is the force of friction experienced by a body when it is at rest.
a) Dynamic
b) Static
c) Sliding
d) Rolling
Answer: b
Clarification: Static friction is the force of friction experienced by a body when it is at rest.
OR Static friction is the value of the limiting friction just before slipping occurs.
2. _____________ friction is the value of the limiting friction just before slipping occurs.
a) Dynamic
b) Static
c) Sliding
d) Rolling
Answer: b
Clarification: Static friction is the force of friction experienced by a body when it is at rest.
OR Static friction is the value of the limiting friction just before slipping occurs.
3. ____________friction is the force of friction experienced by a body when it is in motion.
a) Dynamic
b) Static
c) Sliding
d) Rolling
Answer: a
Clarification: Dynamic friction is the force of friction experienced by a body when it is in motion.
OR Dynamic friction is the value of frictional force after slipping has occurred.
4. _____________ friction is the value of frictional force after slipping has occurred.
a) Dynamic
b) Static
c) Sliding
d) Rolling
Answer: a
Clarification: Dynamic friction is the force of friction experienced by a body when it is in motion.
OR Dynamic friction is the value of frictional force after slipping has occurred.
5. When a body slides over another, the frictional force experienced by the body is known as ____________ friction.
a) sliding
b) rolling
c) static
d) none of the mentioned
Answer: a
Clarification: When a body slides over another, the frictional force experienced by the body is known as sliding friction.
When a body rolls over another, frictional force experienced by the body is known as rolling friction.
6. When a body rolls over another, frictional force experienced by the body is known as _______________ friction.
a) sliding
b) rolling
c) static
d) none of the mentioned
Answer: b
Clarification: When a body slides over another, the frictional force experienced by the body is known as sliding friction.
When a body rolls over another, frictional force experienced by the body is known as rolling friction.
7. Co-efficient of rolling friction is _______________ than co-efficient of sliding friction.
a) greater
b) equal to
c) lesser
d) none of the mentioned
Answer: c
Clarification: For the same pair of surfaces, co-efficient of rolling friction is lesser than co-efficient of sliding friction.
8. Co-efficient of sliding friction for rubber on concrete is
a) 0.030
b) 0.70
c) 0.18
d) 0.004
Answer: b
Clarification: Co-efficient of sliding friction for rubber on concrete is 0.70. When tires made of rubber rolls on concrete, co-efficient of rolling friction becomes 0.030.
9. Co-efficient of sliding friction for steel is
a) 0.030
b) 0.70
c) 0.18
d) 0.004
Answer: c
Clarification: Co-efficient of sliding friction for steel is 0.18. When railway wheels made of steel rolls on rails made of steel, the co-eficient of rolling friction becomes 0.004.
10. The co-efficient of dynamic friction is _______________ than static friction.
a) greater
b) equal to
c) lesser
d) none of the mentioned