Consider what happens when you jump up in the air. Which of the following is the most accurate statement?
A) It is the upward force exerted by the ground that pushes you up, but this force cannot exceed your weight.
B) You are able to spring up because the earth exerts a force upward on you that is greater than the downward force you exert on the earth.
C) Since the ground is stationary, it cannot exert the upward force necessary to propel you into the air. Instead, it is the internal forces of your muscles acting on your body itself that propels your body into the air.
D) When you push down on the earth with a force greater than your weight, the earth will push back with the same magnitude force and thus propel you into the air.
E) When you jump up the earth exerts a force F1 on you and you exert a force F2 on the earth. You go up because F1 > F2.
Answer: D
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