Work done in non-uniform circular motion – Rankers Physics

Dynamics of Circular Motion: Practice Problem & Solution

Assertion (A): The work done by the net force on a particle during non-uniform circular motion is not equal to zero. Reason (R): In case of non-uniform circular motion net force and elementary displacement are not perpendicular to each other.  
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 Dynamics of Circular Motion. Understanding the underlying formula is key to arriving at the correct answer below:

In non-uniform circular motion, there is a tangential component of force, which causes a change in speed. Work done is `\(W = \int \vec{F}_{net} \cdot d\vec{r}\)`.
Since the net force is not always perpendicular to the elementary displacement `\(d\vec{r}\)` due to the tangential component, the work done by the net force is not zero. Both assertion and reason are true, and the reason correctly explains the assertion.

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