Two identical balls `A and B` having velocity of `0.5 m//s and -0.3 m//s` respectively collide elastically in one dimension. The velocities of `B and A` after the collision respectively will be

Options

A. `-0.5m//s "and" 0.3m//s`
B. `0.5m//s "and" -0.3m//s`
C. `-0.3m//s "and" 0.5m//s`
D. `0.3m//s "and" 0.5m//s`

Answer

c

Explanation

(c )Key Idea In elastic collision, kinetic energy of the system remains unchanged and momentum is also conserved.
It is given that mass of balls are same and collision is perfectly elastic (`e=1`) so their velocitie will be interchanged.
Thus. `v_(A)^(')=v_(B)=-0.3m//s`
`v_(B)^(')=v_(A)=0.5m//s`