Question

When a body moves in a circular path, no work is done by the force, since________

• A. There is no net force
• B. There is no displacement
• C. Force is always away from the centre
• D. Force and displacement are perpendicular to each other.

Answer 1

Answer: (D)

When a body moves in a circular path, then centripetal force is always directed towards centre of circular path. Hence, centripetal force and displacement (directed tangentially) are perpendicular to each other.
$\therefore$ Work done
$W=Fs\cos 90^{\circ }=0\left[\because \cos 90^{\circ }=0\right]$