A `1 kg` ball moving at `12 m//s` collides head on with a `2g` ball moving in the opposite direction at `24 m//s`. The velocity of each ball after the impact, if the coefficient of restitution is `2//3` is

Options

A. `-28 m/s, -4 m/s`
B. `28 m/s, -4 m/s`
C. `20 m/s, 24 m/s`
D. `-20 m/s, -4 m/s`

Answer

`(1)`

Explanation

`vec v_(2) = ((m_(1) - em_(2))/(m_(1) + m_(2)))vec u_(1) + ((m_(2)(1 + e))/(m_(1) + m_(2))) vec u_(2)`
`vec v_(2) = ((m_(1)(1+ e))/(m_(1) + m_(2)))vec u_(1) + ((m_(2)-em_(1))/(m_(1) + m_(2))) vec u_(2)`