Draw the free-body diagram for a basketball player

VIDEO TRANSCRIPT

This is Giancoli Answers with Mr. Dychko. Just before the basketball player jumps, their legs are exerting a large force upwards in order to make them jump and that's... Well, the legs are exerting a force downwards on the floor then the floor in turn exerts Newton's third law equal force upwards on the person and that's the normal force exerted by the floor and that is a longer arrow than the gravity downwards since the up force is greater than the town force because they're about to lift off the ground, they accelerate upwards. And then when they're in the air, the only force neglecting friction of course, that's exerting on them is gravity. And so, there's a free body diagram, one arrow pointing down so, they're accelerating downwards. Even though they might initially be moving upwards they will be slowing their upwards motion due to their acceleration downwards because of this net force downwards.