A person applies a constant force on a particle of mass m and finds that the particle moves in a circle of radius r with a uniform speed u as seen from an inertial frame of reference.

Question

Philoid · Accepted Answer

When the particle start moving, there will be some other forces like centrifugal force, frictional force, etc. acting on the particle that will balance the constant applied force F. This will keep the particle moving in the circle. (A) is incorrect and (B) is true.

These other forces will vary at every point along the circular path, both in magnitude and direction to keep balancing the constant applied force F, to keep the particle in the circular motion. Therefore, (C) is incorrect and (D) is true.