A 72kg friend is standing still on rollerskates holding a 5.5kg watermelon. He throws the watermelon forward with a velocity of 3.3m/s. What is his recoil velocity?

A980-kg sports car collides into the rear end of a 2300-kg suv stopped at a red light. the bumpers lock, the brakes are locked, and the two cars skid forward 2.6m before stopping.the police officer, estimating the coefficient of kinetic friction between tires and road to be 0.80, calculates the speed of the sports car at impact. what was that speed?