State if each of the following statements is true or false. Give reasons for your answer.
A. In an elastic collision of two bodies, the momentum and energy of each body is conserved.
B. Total energy of a system is always conserved, no matter what internal and external forces on the body are present.
C. Work done in the motion of a body over a closed loop is zero for every force in nature.
D. In an inelastic collision, the final kinetic energy is always less than the initial kinetic energy of the system.
A. False
Explanation: In an elastic collision, the energy and momentum of the entire system is conserved and not of individual bodies.
B. False
Explanation: External forces can do work on the system and hence, they can change the total energy of the system.
C. False
Explanation: Work done in the motion of a body over a closed loop is zero only for conservative forces.
D. True
Explanation: In inelastic collisions, the final kinetic energy is always less than the initial kinetic energy because some of the energy is lost during the process in the form of sound, heat, etc.