The discussion revolves around the concept of static friction and its ability to do work on an object. Participants are examining the conditions under which static friction may or may not perform work, particularly in different reference frames.
The discussion is active, with various interpretations being explored regarding the relationship between static friction and work. Some participants have provided examples and counterexamples, while others are questioning the implications of reference frames on the concept of work.
There is an ongoing debate about the definitions and assumptions related to work and static friction, particularly in relation to different inertial and non-inertial frames of reference.
Chestermiller said:Work always depends on the reference frame.
Chet
Yes. You hit the nail on the head. Consider the case of a box on a conveyor belt, and the speed of the belt is increasing with time. So the frictional force is causing the box to accelerate, and the box is gaining kinetic energy. Now consider this same situation from the perspective of an accelerating frame of reference that is moving with the box. From this frame of reference, the frictional force is not doing any work, and the box is not accelerating. The frictional force is being balanced by the apparent horizontal body force acting on the box (associated with the acceleration).VictorH said:Why does work depend of the reference frame? If we do work isn't it the change of kinetic energy equal for all observers? The velocity vectors may change, of course, but the difference shouldn't for two inertial frames. Is it different for non-inertial frames?