A marble moves along the x-axis. The potential-energy functionis shown in Fig. 1a) At which of the labeled x-coordinates is the force on the marble zero?b) Which of the labeled x-coordinates is a position of stable equilibrium?c) Which of the labeled x-coordinates is a position of unstable equilibrium?

Question

estenutC · Accepted Answer

a.) The force is zero when the slope of the graph is zero, soit is at points B and D. b.) Point B is at a stable equilibrium because you would needto use energy to move the marble away at point B. c.) Point D is at a unstable equilibrium because in order tomove the marble away from point D, the potential energy would decrease, therefore the kinetic energy would increase making it unstable.