A moving block having mass `m` , collides with another stationary block having mass `4m`. The lighter block comes to rest after collision. When the initial velocity of the block is `v`, then the value of coefficient of restitution `( e)` will be

Options

A. 0.8
B. 0.4
C. 0.25
D. 0.5

Answer

C

Explanation

`mv = 4 m v_(2) implies v_(2) = (v)/(4)`
`v_(1) - v_(2) = - e (u_(1) - u_(2))`
`0 - (v)/(4) = - e (v - 0)`
`e = (1)/(4) = 0.25`