a. A=B=C. b. A=B=C. c. A=B=C. d. B, A, C.
Work Step by Step
a. They start at the same height, so their initial PEs are the same. b. They have the same mass and start with the same speed, so their initial KEs are the same. c. The total energy, sum of KE and PE, remains constant. They started with the same total energy, and end with the same PE (because their heights are the same), so the final KEs are the same. d. Looking at the vertical velocity components only, which will determine the time in the air, the ball that is thrown upward will stay airborne longest. The horizontally thrown ball is next, and the ball that is thrown downward will hit the ground first.