Question

In which of the following cases forces may not be required to keep the

• A. Particle going in a circle
• B. Particle going along a straight line
• C. The momentum of the particle constant
• D. Acceleration of the particle constant

Answer 1

Answer: (C)

The momentum of the particle constant

Answer 2

If momentum remains constant then force will be zero because $F = \frac{dP}{dt}$