Friction and Work Done in Rolling – Rankers Physics

Rolling: Practice Problem & Solution

Assertion (A): A body is rolling without slipping on a surface. There must be frictional force to start such a motion. Reason (R): In rolling without slipping, work done against the frictional force is zero on rolling body.  
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Rolling. Understanding the underlying formula is key to arriving at the correct answer below:

Assertion (A) is true: Friction provides the necessary torque to initiate the angular acceleration required for rolling.

Reason (R) is true: In pure rolling, the point of contact is instantaneously at rest, so the work done by static friction is zero. Both statements are true, but R does not explain A.

Leave a Reply

Your email address will not be published. Required fields are marked *

Similar Practice Questions

Explore conceptually related problems to test your knowledge.

1. A particle is moving along a straight line parallel to x-axis with constant velocity. Its angular momentum about the origin:
2. Three point masses \(m\), \(2m\) and \(3m\) are located at the vertices of an equilateral triangle of side length \(L\). The moment of inertia of the system about an axis passing through mid-point of the side (connecting \(m\) and \(2m\)) and perpendicular to the plane of the triangle, is
3. From a circular disc of radius $R$ and mass $9M$, a small disc of mass $M$ and radius $\frac{R}{3}$ is removed concentrically. The moment of inertia of the remaining disc about an axis perpendicular to the plane of the disc and passing through its center is: (2010 Mains)
4. The ratio of the accelerations for a solid sphere (mass m and radius R) rolling down an incline of angle $theta$ without slipping and slipping down the incline without rolling is: (2014)
5. Moment of inertia of a uniform circular disc about a diameter is $I$. Its moment of inertia about an axis perpendicular to its plane and passing through a point on its rim will be: (1990)