Multiple choice

A particle moves in a circle of radius R with a constant speed under a centripetal force F. The magnitude of work done in completing a full circle will be-

  1. 2RF

  2. πR2F

  3. 2πRF

  4. Zero
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Work done is zero because centripetal force is always perpendicular to the displacement of the particle. Since work = F × d × cos(θ) and θ = 90° throughout circular motion, cos(90°) = 0, making work done zero regardless of the number of revolutions completed.

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