Consider an one dimensional elastic collision between a given incoming body A and body B, initially at rest. The mass of B in comparison to the mass of A in order that B should move with greatest kinetic energy is

Options

A. `m_(B) gt gt m_(A)`
B. `m_(a) lt lt m_(A)`
C. `m_(B) = m_(A)`
D. can't say anything

Answer

C)

Explanation

Velocity of block B after collision `v_(2) = (2m_(A)u_(I))/(m_(A)+m_(B))`
KE of block `B = 1/2m_(B)v_(2)^(2) = 1/2m_(B)[4m_(A)^(2) u_(1)^(2)/(m_(A) + m_(B)^(2))] = 2m_(A)^(2)m_(B)/(m_(A)+m_(B)^(2))u_(1)^(2)`
which is maximum if `m_(A) = m_(B)`