A car of mass 600kg is moving at speed of 20m/s.it colldies with a sanitary car of mass 900kg.if the first car bounces back at 4m/s,at what speed does the second car move after the collision?
momentum is conserved
600 * 20 = (600 * -4) + (900 * v)
600 * 20 = (600 * -4) + (900 * v)