question_answer 29)

Which of the following potential energy curves Fig. 6.55 cannot possibly describe the elastic collision of two billiard balls ? Here r is the distance between centres of the balls.                                                                 

Answer:

                During the short time of collision, the kinetic energy gets converted into potential energy. But the P.E. of a system of two masses varies inversely as the distance between them, i.e., . Hence all the potential energy curves except the one shown in Fig.  cannot describe an elastic collision.