I am having a real problem with this question. Through the process of doing work, energy can move between the external world and the system as the result of forces or work. I say it's forces, but someone else says it's work because only work and energy can be inerchanged. Who is right?

Question

Energy can enter a system from the external world as a result of either work or heat transfer. Forces alone are not enough. The forces must cause something to move, and do work.