Free fall question?

Question

If I were in an elevator that were free falling, why would the normal contact force of the floor on me decrease resulting in a feeling of weightlessness?

Answer 1

The reason is because YOU and the elavator is accelerating due to the earth's gravitational pull. The person and the elevator is accelerating toward the surface of the earth at 9.81 m/s^2. Because the elevator is falling downward at the same rate as the person, we can say the person doesn't have "time" to make contact with the elevator floor.

We can also say you are chasing the elevator. You would have to fall faster to make contact with the ground.

According to Einstein, an acceleration can cancel out another acceleration.

Answer 2

The "contact force" of the elevator is an illusion. You are pushing down on the elevator car; it resists your pushing. You are pushing down with your mass times the acceleration of gravity. Since you are unable to accelerate, the car feels your mass at rest...we call that "weight"...you call it "contact force".

When the car suddenly free-falls, the car is no longer stopping you from accelerating, so it is no longer resisting your pushing, thus you have no "weight" or "contact force" because you are both suddenly without resistance to the acceleration of gravity. You are not "weightless", you are only weightless with respect to the elevator because you are both accelerating at the same rate in a constant gravitational field.

You will actually come off the floor of the elevator because your feet will probably "push" slightly, and the net effect will be to move you off the floor (your muscles are always flexed when you stand). This is the same thing you see when astronauts push off the walls of their spacecraft while in orbit...which is actually a free-fall with a curvature that matches the curvature of the earth, so they never hit because the ground is always the same distance away.

So, you feel "weightless" because there is no "resistance" to your acceleration, thus, no "weight"....but that will change as soon as your elevator car hits the bottom floor :)

Answer 3

U feel a normal contact force coz force due to ur weight is balanced by reaction force of ground on ur body at usual time,so u feel a contact force but when both elevator and u are accelarating reaction force bcome 0 so no force feeled

Answer 4

You and the floor would be falling at the same rate and acceleration in free fall. That would be like running at 15mph to push a car that is running at 15mph. It will keep going whether or not you apply pressure.

Answer 5

Because you would be free-falling as well, and at the same rate as the elevator.

When something free-falls in a gravitational field, the accellerational frame of reference that it experiences is equivalent to zero gravity.




.