Hello all, I have some confusion about rotating. The bad thing is that I don't know where the point is which my confusion starts. As I want to check also my fundamental knowledge about the topic I will ask my questions step by step to see where my problem begins. I hope you don't mind. My first questions are those: Let us roll a rigid cylinder on a rigid surface (whose height is always h=0), we only give the first velocity, after that there is no force on the system externally applied. - I think the only forces exert on the cylinder are the weight of the cylinder, the vertical reaction force exerted by the ground and the horizontal friction force which is in the same direction with the movement of the center of mass. Is it right? - If so, the total horizontal force is the frictional force. As it is in the same direction with the movement of the center of mass will the cylinder accelerate forever?