Question

Assertion (A): When the displacement is normal to the direction of force, the work done is zero.

Reason (R): Work done depends on the angle between force and displacement.

Options

• both A and R are true and R is the correct explanation of A.

• both A and R are true and R is not the correct explanation of A.

• assertion is false but reason is true.

• assertion is true but reason is false.

Answer 1

Both A and R are true and R is the correct explanation of A.

Explanation:

When displacement is normal to the force, \[\theta = 90^\circ\] and \[W = FS\cos 90^\circ = 0\], so the assertion is true. Work done depends on the angle between force and displacement through \[\cos\theta\], so the reason is also true and correctly explains the assertion.