A block A moves horizontally under the action of a force F whose line of action is paralle...

A block A moves horizontally under the action of a force F whose line of action is parallel to the motion. If the kinetic energy of A as a function of x is that shown (x1 and x2 are extrema for TA), what can you say about the sign of F for x0 < x < x1 and x1 < x < x2?

Note:Concept problems are about explanations, not computations.

Figure P4.21