Question

The work done by a centripetal force

• A. increases by decreasing the radius of the circle
• B. decreases by increasing the radius of the circle
• C. increases by increasing the mass of the body
• D. is always zero

Answer 1

The correct option is D

is always zero

1. For a body moving along a curved path, a centripetal force acts on it.
2. The centripetal force acts along the radius of the path and is directed towards the center.
3. The displacement of the body in a circular path is always along the tangent.
4. As the radius is perpendicular to the tangent, the direction of centripetal force is perpendicular to the displacement.
5. When force and displacement are perpendicular to each other, the work done is zero.
6. $W=FS\cos 90°=0$

Thus, the work done by a centripetal force is always zero.

Hence, option D is correct.