Question

A boy on roller blades throws a jug of water away from himself, giving it a speed of 10 m/s. The boy's mass is 50 kg and the mass of the jug and water is 9 kg. What is the velocity gained by the boy?

Answer 1

momentum is conserved.
initialmomentum=finalmomentum
0=9(10)+50V
solve for V. Notice its direction (sign).