Friction and Relative Motion – Rankers Physics

Friction: Practice Problem & Solution

Assertion (A): A man starts walking towards west. Friction force on him acts towards east. Reason (R): Friction opposes relative motion.  
(1) Both (A) & (R) are true and the (R) is the correct explanation of the (A)
(2) Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(3) (A) is true but (R) is false
(4) Both (A) and (R) are false

Solution Explained:

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

Assertion (A) is false; when walking west, the static friction force on the man acts west, in the direction of motion. Reason (R) is true as friction fundamentally opposes relative motion. Thus, (A) is false and (R) is true. Option (4) is selected as it correctly identifies (A) as false.

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Similar Practice Questions

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1. A \(3.0\text{ kg}\) mass is moving in a plane, with its x and y coordinates given by \(x = 24t^2 - 1\) and \(y = 3t^3 + 2\), where x and y are in meters and t is in second. Find the magnitude of the net force acting on this mass at \(t = 2\text{ sec}\).
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