If a gasoline engine has an efficiency of 21 percent and losses 780 j to the cooling system and exhaust during each cycle, how much work is done by the engine?

Ahockey player of mass 82 kg is traveling north with a velocity of 4.1 meters per second he collides with the 76 kg player traveling east at 3.4 meters per second if the two players locked together momentarily in what direction will they be going immediately after the collision how fast will they be moving