1. The problem statement, all variables and given/known data A tennis ball is rolled across a carpet. Explain the forces exerted on the ball by the person rolling it and the forces that bring it to rest. 2. Relevant equations 3. The attempt at a solution The hand exerts an impulse on the tennis ball which causes a change in momentum and then it starts to roll. Air resistance will act on the ball which will slowly bring it to rest. Could someone help me understand if friction applies. I did some reading and apparently you can only ever get friction between the object and the floor if there is some dynamic friction. The reason is that static friction by definition can do no work against the motion of any object so if the object is not moving relative to the surface then friction from the surface can never oppose the motion of an object. Is this right? So if a roller coaster or a car are in motion, so long as the wheels never slip, friction from the surface can never slow the object down? If we assume no dynamic friction on the tennis ball across the carpet then is the only loss of motion through air resistance?