Two identical balls collide head on. The initial velocity of one is `0.75 ms^(-1)` , while that of the other is `-0.43 ms^(-1)`. If the collision is perfectly elastic, then their respective final velocities are

Options

A. `0.75ms^(-1) , -0.43 ms^(-2)`
B. `-0.43 ms^(-1) , 0.75 ms^(-1)`
C. `-0.75 ms^(-1) , 0.43 ms^(-1)`
D. `0.43 ms^(-1) , 0.75 ms^(-1)`

Answer

B

Explanation

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