A car of mass 800kg is moving at a speed of 20m/s.it collide with a stationary car of mass 1600kg,if the first car bounce back at 4m/s. at what speed does the second car have after the collision?
Let the speed of the second car after the collision be V.
By conservation of momentum:
(800kg)(20m/s) = (800kg)(4m/s) + (1600kg)V
16000 = 3200 + 1600V
1600V = 12800
V = 8 m/s
Therefore, the second car has a speed of 8 m/s after the collision.