Solution
In this question we have given
mass of bowling ball=8kg
Velocity of bowling ball= 7m/s
mass of pain=2kg
velocity of pain=12m/s
In this case, law of conservation of momentum will be applied. According to law of conservation of momentum,
initial momentum of system= final momentum of the system
Total initial momentum of the system =mass of bowling ball* Velocity of bowling ball
=8 kg x 7 m/s
= 56 kg m/s.
momentum of the pain after getting hit is =mass of pain* velocity of pain
=2kg*12m/s
=24 kg m/s.
So the momentum of the bowling ball after hitting the pain= 56 kg m/s - 24 kg m/s
= 32 kg m/s
velocity of the bowling ball after hitting the pain = momentum of the bowling ball after hitting the pain/mass of bowling ball
=32 kg m/s / 8 kg
= 4 m/s
Therfore, velocity of the bowling ball after hitting the pain is 4m/s