Question

Assertion (A): When a coolie walks on the horizontal ground while carrying a load on his head, no work is done against the force of gravity.

Reason (R): The coolie does work against the force of friction when he moves with load.

Options

• Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion.

• Both Assertion (A) and Reason (R) are true but Reason (R) is not the correction explanation of Assertion.

• Assertion (A) is false, but Reason (R) is true.

• Assertion (A) is true, but Reason (R) is false.

Answer 1

Both Assertion (A) and Reason (R) are true but Reason (R) is not the correction explanation of Assertion.

Explanation:

The assertion statement is correct because the load moves horizontally while the force of gravity acts vertically downward. Since the angle between the force and displacement is 90°, no work is done against gravity. At the same time, the reason statement is also correct because the coolie has to perform work to overcome the force of friction while walking along the road with the load. However, the fact that work is done against friction does not explain why the work done against gravity is zero.