A steel ball of mass `2m` suffersone-dimensional elastic collision with a row of three steel balls, each of mass m. If mass `2m` has collided with velocity `v` and the three balls numbered `1,2,3` were initially at `2`. rest, then after the collision

Options

A. balls `1,2` and `3` would start moving to the right, each with velocity `v//3`
B. balls `2` and `3` would start moving to the right, each with velocity `v//2`
C. balls `2` and `3` start moving to the right, each with velocity `v`
D. ball `2` and ball of mass `2m` would remain at rest

Answer

C, D

Explanation

In option a neither momentum nor kinetic energy is conserved collision is not elastic. Hence, option a is not correct.
b. Same difficulty lies with option b. so only option c and d correct.