The figure below shows two balls: ball A and ball B. Initially, ball A is moving at 20 m/s and ball B is stationary. After the collision, ball A is moving at 10 m/s. We need to determine the velocity of ball B after the collision. We can assume that the collision between the two balls is elastic, meaning that momentum is conserved. Therefore, the momentum before the collision is equal to the momentum after the collision.
Before collision:
Ball A: mass = 30 kg, velocity = 20 m/s
Ball B: mass = 9 kg, velocity = 0 m/s
After collision:
Ball A: mass = 30 kg, velocity = 10 m/s
Ball B: mass = 9 kg, velocity = ? m/s
Using the equation for conservation of momentum:
(mass of ball A x velocity of ball A) + (mass of ball B x velocity of ball B) = (mass of ball A x final velocity of ball A) + (mass of ball B x final velocity of ball B)
(30 kg x 20 m/s) + (9 kg x 0 m/s) = (30 kg x 10 m/s) + (9 kg x final velocity of ball B)
Simplifying the equation:
600 kg m/s = 300 kg m/s + 9 kg x final velocity of ball B
Subtracting 300 kg m/s from both sides:
300 kg m/s = 9 kg x final velocity of ball B
Dividing both sides by 9 kg:
33.33 m/s = final velocity of ball B
Therefore, the velocity of ball B after the collision is 33.33 m/s.