Which of the following statements is correct?

Options

A. (a) Kinetic energy of a system can be changed without changing its momentum.
B. (b) Kinetic energy of a system cannot be changed without changing its momentum.
C. (c) Momentum of a system cannot be changed without changing its kinetic energy.
D. (d) A system cannot have energy without having momentum.

Answer

A

Explanation

In the explosion of a bomb or inelastic collision between two bodies as force is internal, momentum is conserved while KE changes. Hence, the KE of a system can be changed without changing its momentum. Similarly, the reverse is also true, e.g., if a force acts perpendicular to motion, work done will be zero and so KE will remain constant. However, the force will change the direction of motion and so the momentum.
Further, body may have energy (i.e., potential energy) without having momentum.