Sorry...I hope I'm not annoying anyone. I really have tried to figure out how to do these, but I jsut can't get it. I hate jsut throwing problems out there, but I dont really have a better way of doing it. "Karmen is playing pool, and strikes a 0.25 kg ball, making it go 1.5 m/s. If Karmen used the force of the cue on the ball with 20 N, over what distance did it act?" I think I should use W=Fd at some point, but still, that gives W=20d which still doesnt get anywehere. "A 30 kg shopping cart is on a 2m hill and rolls down to hit a stump at the very bottom. At impact, a .25 kg can flies and hits a car with an average force of 490N. How deep is the dent?" I think we are supposed to assume the metal did work in stopping it. I really don't know!