The work done on a system by external forces is equal to the change in its

Step-by-step solution

According to the work-energy theorem, the work done by all forces (external and internal) on a system is equal to the change in its kinetic energy: W_ ext + W_ int = K The internal work done can be split into work done by conservative internal forces and non-conservative internal forces: W_ int = W_ int, c + W_ int, nc The work done by conservative internal forces is equal to the negative of the change in potential energy: W_ int, c = - U The work done by non-conservative internal forces results in a change in the