## Questions 18-19
A ball swings freely back and forth in an arc from point I to point IV, as shown. Point II is the lowest point in the path, III is located 0.5 meter above II, and IV is I meter above II. Air resistance is negligible.
18. If the potential energy is zero at point II, where will the kinetic and potential energies of the ball be equal?
(A) At point II
(B) At some point between II and III
(C) At point III
(D) At some point between III and IV
19. The speed of the ball at point II is most nearly
(A) 3.0m/s
(B) 4.5m/s
(C) 9.8m/s
(D) 14m/s