Rolling Motion
A solid homogenous sphere of mass and radius is moving on a rough horizontal surface, partly rolling and partly sliding. During this kind of motion of this sphere
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Answer: (b)
- (a) Kinetic friction does work during slipping, so total KE is not conserved.
- (b) Friction acts at the contact point and gravity and normal pass through the line of it, so torque about the contact point is zero: this angular momentum is conserved.
- (c), (d) Friction has a torque about the centre, so spin KE and angular momentum about the centre change.
- So the answer is (b).