If the elevator is already descending, a positive acceleration will cause it to move faster. Here we deal with yet another kind of question. The downward acceleration of the elevator makes it feel as if the force of gravity has changed. Imagine you are in an elevator in free fall, and suppose you drop a penny. As you start to descend, the acceleration of the elevator is in the same direction as the force due to gravity.
Gravity is the only force acting on it.
The sliders allow you to experiment. With the top one you can enter a person s weight, while the bottom one sets the acceleration of the elevator. On this screen, like the previous one, the acceleration is always downward. An elevator is usually balanced by a counterweight. In the illustration, the counterweight is the small cylinder on the left, while the elevator is represented by the larger box.