Question

in pure rolling motion (a) Force of friction does zero work on the body (b) Linear velocity of centre of mass is always zero (c) Angular velocity of body about centre of mass is always zero. (d) Centre of mass always moves with constant velocity​

Answer 1

ing with uniform angular speed w about a fixed axis ... its center 

Answer 2

In pure rolling motion:

a) True

Because as the body will start rolling, the acceleration of the bottom point touching the surface will be zero, we can say that displacement will be zero. Therefore, work done by friction force will also be zero.

b) False

The velocity of the Centre of mass will be Vcm that will be equal to Rω, where R is the radius of the body, ω is angular velocity.

c) True

ω is the angular velocity about the centre, therefore we can say that Angular velocity of body about centre of mass is always zero

d) True

the centre of mass will always move with a constant velocity that is Rω.