Two solid rubber balls A and B having masses 200 and 400 g respectively are moving in opposite directions with velocity of A equal to 0.3 m/s. After collision the two balls come to rest, then find the velocity of B.

Two solid rubber balls A and B having masses 200 and 400 g respectivel

1.	Two solid rubber balls A and B having masses 200 and 400 g respectively are moving in opposite directions with velocity of A equal to 0.3 m/s. After collision the two balls come to rest, then find the velocity of B.
Answer» SOLUTION :Initial linear MOMENTUM of system `= m _(A) v _(A) = m _(B) v _(B)` `= 0.2 xx 0.3 +0.4 xx v_(B)` FINALLY both BALLS come to rest `therefore `Final linear momentum = 0 By the law of conservation of linear momentum `0.2 xx 0.3 +0.4 xx v _(B) =0` `therefore u _(B)= (0.2xx 0.3)/( 0.4) =- 0.15 m//s`