Frictional Force in Circular Motion – Rankers Physics

Uniform Circular Motion: Practice Problem & Solution

Assertion (A): A cyclist is cycling on a rough horizontal circular track with increasing speed. Then the net frictional force on cycle is always directed towards centre of the circular track. Reason (R): For a particle moving in a circle, component of its acceleration towards centre, that is, centripetal acceleration should exist (except when speed is zero instantaneously).  
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 Uniform Circular Motion. Understanding the underlying formula is key to arriving at the correct answer below:

Assertion (A) is false. For increasing speed, friction must provide both a tangential force (for speed increase) and a centripetal force (for circular path). Thus, the net frictional force is not solely towards the center. Reason (R) is true, centripetal acceleration is necessary for circular motion whenever speed is non-zero. Since A is false and R is true, and this specific option is not available, we choose option (4) as the closest available if compelled.

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Similar Practice Questions

Explore conceptually related problems to test your knowledge.

1. Assertion (A): In uniform circular motion of a body, its linear speed remains constant. Reason (R): In uniform circular motion total acceleration of the body has no radial component.  
2. Assertion (A): If a particle is moving on a curved path its \( \frac{d|\vec{v}|}{dt} \) may be zero. Reason (R): A particle can move on curved path without any acceleration.  
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