(Apparent Weightlessness)

On a Roller Coaster

In order to feel weight there must be a "reaction" force.

If you jump out of a window, you would fell weightless. Weightless because there is no reaction force pushing up on your feet.
FREE FALL (Weightlessness): ACTIVITY 1
Materials: cup (with holes), water, chair, paper towels, trash can
Poke two holes on opposite sides of the bottom of the cup. Stand in a chair. Hold the cup with your fingers over the holes. Fill the cup 1/3 the way with water. Hold the cup with your other hand. Briefly remove your fingers from the holes. Observe what happens. Cover the holes again with your fingers. Hold the cup up as high as possible. Drop the cup and observe what happens to the water this time.

Why doesn't the water come out of the holes when it is dropped?

When on the roller coaster below do you think you are weightless?

Swing the apparatus around with a superball in the cup. STAND CLEAR OF ANYONE ELSE AROUND YOU . Swing is just slow enough so the ball does not fall out.

Take whatever measurements you need to calculate the centripetal acceleration of the ball in the cup. ____________.

How many g's is this? _________g's .

The use of phase "apparent weightlessness" is because the in freefall the rider does not feel the ractio force of the chair on his or her bottom. This gives the sensation of weightlessness. He or she does not feel hte reaction force of the seat because the rider is moving vertically at 9.80 m/s2 and so is the roller coaster car. Weight is defined as your mass times the acceleration of gravity. As you fall, gravity is accelerating you down at 9.80 m/s2 -it is not zero.

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