A ball moving with a velocity v  collides elastically with another ball of equal mass, in a one dimensional collision. Which of the following is not possible ?

Q: A ball moving with a velocity $\vec{v}$  collides elastically with another ball of equal mass, in a one dimensional collision. Which of the following is not possible ?

(a) First ball will come to rest

(b) Second ball will move with a velocity $\vec{v}$

(c) Both balls will move with velocity $\vec{v}$ after collision

(d) The first ball will move with a velocity less that $\vec{v}$

Ans: (c)