If you were in an elevator and it suddenly dropped three floors, is it possible that if you jumped up the exa?

Question

exact split second it hit the ground. Would it help your chances of not getting injured as bad?

Answer 1

It wouldn't help I'm afraid. This was covered in a Mythbusters episode.

Answer 2

Since you asked only if it would "help your chances of not getting injured as bad", the answer is clearly yes.

Important assumptions:
1) Your chances of injury are proportional to the speed you hit the elevator floor with

2) The elevator has much more mass than your body.

3) Your jump is timed to reach maximum velocity relative to the floor just before it stops instantaneously.

4) You are able to assume a crouched position on the elevator floor waiting for the moment of impact


Reasoning: Call it a 10 meter drop. From the formula v = sqrt(2gx) the velocity at impact is 14 m/s. If you can obtain an upward velocity of 2m/s, then your body's speed at impact will be only 12m/s.

QED

Answer 3

It's an interesting question because the answer is, "It depends." If the elevator is in free fall, you will be accelerating at the same rate and, relative to the cab, will experience zero-g. You'd float, and not be able to push against the floor. Safety systems, from inspections to rail brakes, make a free fall practically impossible.

If the cab falls but there's resistance (this is slightly more likely), you can still push against the floor. In that case, you could decrease your downward velocity, and slightly increase the downward velocity of the cab. Conservation of energy applies here, also--another way to approach the problem. You could, with simplified assumptions (mostly about the recoil of the cab), be traveling at a slightly lower speed on impact. Whether this would make a difference depends on the velocity before impact, and how much energy the jump involved. Probably not enough to make a difference. But it's still an interesting problem that partly answers the question, "Who says physics teachers don't have a sense of humor?"

Answer 4

It would do more damage. You don't have the ability to overcome the force of falling in an elevator. Lets say 3 floors is 10m. So basically you fall for 1 second. This means you are falling at a speed of (roughly) 10m\s or 22.5mph. So falling in an elevator is a lot like being hit by a car. If you jump backwards from a moving car you are going to get hurt. In the case of the elevator it is better to lie down thereby distributing the force over you entire body instead of just your feet. (Force is pressure times unit area-smaller area more pressure for a given force-your weight times acceleration)

Answer 5

You would hit the ground with the same vertical speed as the elevator would hit the ground. It would make no difference at what stage you jump out you still will be under gravitational acceleration
Relative to the moving elevator floor your velocity will be zero.
But relative to the statibnary ground surface your velocity will progressively increase until you hiy the grounf with the acquired free fall velocity

Answer 6

actually, if you jumped at the last second you will be able to cancel some amount of your downward velocity

if you can jump maybe 2 feet in the air (if you're a good jumper) then you could completely cancel a 2-foot fall

if you are falling 3 floors (or about 30 feet), you could, by jumping, make your velocity at impact ve the same as if you had fallen only 28 feet

so, the effect of jumping is pretty small

Answer 7

Because it takes a period of time for you to actually be jumping, beginning your jump at the time the elevator hits the ground, I'm afraid you started the jump a little too late... ...Sorry...

Answer 8

Your chances might improve until you hit your head on the ceiling of the elevator, which will be coming down at you once you leave the floor.

Answer 9

Sure, by about 3%. Terminal velocity is on the order of 60 mph. By jumping, you might cut that down to 58 mph.

Answer 10

As the elevator falls, the "g-force" (gravity ) increases. You would not be able to jump, because the increase in g-force will hold you to the elevator floor.