A particle of mass m moving with velocity u collides elastically with a particle of mass 3m at rest. After collision the heavier particle moves with velocity

A particle of mass m moving with velocity u collides elastically with

1.	A particle of mass m moving with velocity u collides elastically with a particle of mass 3m at rest. After collision the heavier particle moves with velocity
Answer» 3u `(U)/(3)` `(u)/(2)` 2u Answer :C