Read each statement below carefully, and state, with reasons, if it is true or false;

(a) During rolling, the force of friction acts in the same direction as the direction of motion of the CM of the body.

(b) The instantaneous speed of the point of contact during rolling is zero.

(c) The instantaneous acceleration of the point of contact during rolling is zero.

(d) For perfect rolling motion, work done against friction is zero.

(e) A wheel moving down a perfectly frictionless inclined plane will undergo slipping (not rolling) motion.

Asked by Abhisek | 1 year ago |  197

1 Answer

Solution :-

Right answer is (a) False. 

Explanation:-

The direction of frictional force is opposite to the direction of motion of the centre of mass. In case of rolling object, the centre of mass moves backwards so the frictional force acts in the forward direction

Right answer is (b) True. 

Explanation:-

During rolling the point of the body in contact with the ground does not move ahead (this would be slipping) instead it only touches the ground for an instant and lifts off following a curve. Thus, only if the point of contact remains in touch with the ground and moves forward will the instantaneous speed not be equal to zero.

Right answer is (c) False. 

Explanation:-

For a rolling object instantaneous acceleration will have a value it is not zero

Right answer is (d) True

Explanation:-

This is because during perfect rolling frictional force is zero so work done against it is zero.

Right answer is (e) True. 

Explanation:-

Rolling occurs only when there is a frictional force to provide the torque so in the absence of friction the wheel simply slips down the plane under the influence of its weight.

Answered by Pragya Singh | 1 year ago

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