Consider a car is accelerating and its tires are not slipping ,just rolling.what is the force on the car that changes its kinetic energy? Some people say in the definition of work dw=F.dx that dx is the displacement of where the force is applied, so the work of friction on the car is zero becouse the down surface part of tires dont move with respect to road.is this correct? I think that work energy theorem states that the work of external forces on a body equls the change in the kinetic energy of center of mass,not where the force is applied.
please tell me if the work done by friction is zero,and our system is the car with its tires,which force cause the change in the kinetic energy of center of mass of the car?is its work zero?why? If zero how to justify work energy theorem?
(Be careful not to use the internal force for this theorem becouse best cars with best engines cant move on a sliding road like greasy road!the internal force cause if friction exist the care moves)