Two smooth spheres A and B of equal radii but masses 1 kg and 2 kg move with speeds 21m/s and 4 m/s respectively in opposite directions and collide. The velocity of A is reduced to 1 m/s in the same direction. Then, which of the following statements is incorrect?

Explanation

Before collision

After collision

By conservation of momentum,
`I(21)+2(-4)=1(1)+2(V_(2))`
`v_(2)=+6m//s`
`thereforev_(2)=6m//s` and its direction is reversed
`e=(6-1)/(21+4)=0.2`
Loss in K.E. `=[(1)/(2)xx1=(21)^(2)+(1)/(2)xx2xx4^(2)]`
`-[(1)/(2)xx1xx(1)^(2)+(1)/(2)xx2xx6^(2)]`
=200J
Impulse on the spheres due to each other
`=1xx21-1xx1=20Ns`.