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A : Work done by friction can increase ...

A : Work done by friction can increase the kinetic energy of the body.
R : Friction is a type of contact force and it always opposes the relative motion or tendency of relative motion.

A

If both assertion and reason are correct and reason is the correct explanation of the assertion.

B

If both assertion and reason are correct but reason is not the correct explanation of assertion

C

If assertion is correct but reason is incorrect.

D

If assertion is incorrect but reason is correct

Text Solution

Verified by Experts

The correct Answer is:
A
Weight and normal reaction pass through centre of sphere hence cannot apply torque about the centre of sphere. Component of weight along the inclined plane tries to translate the sphere and inclined surface below it tries to oppose its motion by applying friction up the plane. And now this force of friction applies torque about the centre of sphere which enables it roll down the plane.
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