40. III a. FIGURE P11.40a shows the force F, exerted on a particle that moves along the x-axis. Draw a graph of the particle's po- tential energy as a function of position x. Let U be zero at x = 0 m. b. FIGURE P11.40b shows the potential energy U of a particle that moves along the x-axis. Draw a graph of the force F as a function of position x.\f