if you were in a falling lift and you jumped high enough just before it hit the bottom, would you be hurt?

Answer 1

Yes, it's a myth that you can escape injury by jumping right before. On the show "Mythbusters" ( http://www.tv.com/mythbusters/elevator-of-death-levitation-machine/episode/368719/summary.html ) the damage to a dummy was extensive!

Answer 2

Yes, because from the moment the lift, with you in it, started falling, you were accellerating downwards at just under 32 feet per second per second until the lift reached a terminal velocity (which would depend on local air resistance) of about 120 to 160 miles per hour. This is the speed at which the lift and everything in it would hit the bottom of the lift shaft. Jumping before impact would have almost no effect because even assuming you could judge the right moment to jump, humans can not jump fast enough to offset by any useful amount, the speed at which you are falling. If the lift had fallen more than about 10 feet you would sustain progressively more serious injury. Most impacts after falling more than 30 feet would tend to be fatal. Remember what you would be hitting would be the floor of the lift, which is usually pretty hard.

Answer 3

Assuming the lift had no roof and the thing didn't explode when it reached the bottom then it is theoretically possible as has been mentioned before. You don't mention at what speed the lift is falling. If it's in freefall then Terminal Velocity is about 120mph and no human can jump that fast. However if you had, say, some powerful springs on your feet you could do it. Rather than try it in a falling lift though, just try measuring your speed as you jump up from solid ground. (I don't know how you could do that but those of you brainier than I can explain.) If you can travel faster than the falling speed of the lift you could do it.

Actually, thinking about it a little more, if you could jump at the same speed as the falling lift you would be stationary for a few moments thereby giving you enough time to calmy grab hold of something and swing out like a monkey... :o)

Answer 4

The tricky part is "high enough". A human can jump what, 3 feet?The elevator is falling a good deal faster. The velocity of the jump will be subtracted from the velocity of the impact if the timing is right.

Take a basketball player, 100 kg with vertical jump of 3 feet. Since gravity accelerates 32f/s^2downward, his initial velocity is:

v = 32t
v/2*t = 3, vt = 6
32t^2 = 6, t^2 = 6/32 = 3/16, t = sqrt(3)/4, v = 8*sqrt(3) is about 14 f/s.

If the elevator has fallen 16 feet (1 1/2 stories) the impact velocity is 32f/s. If it has fallen 32 feet (3 stories) the impact velocity is 64f/s. If it has fallen 64 feet (6 stories) the impact is 128f/s. The athlete's jump will take about half a story off the fall if it is timed just right. I wouldn't look for him back on the basketball court for a while.

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By the way, you can throw out references to terminal velocity, that figure is for a person falling. An elevator falling would have a completely different terminal velocity, so while practically it is relevent, the actual value is too unknown (faster because heavier/denser? Slower because of friction and air compressing in the shaft?)

Answer 5

Absolutely.

As a matter of fact... you probably would not be able to 'jump' as you would already be 'floating' inside the lift/elevator.

Here's the physics of the process....

Your elevator is at the top of 20 story building with you inside. The elevator has the 'potential energy' of the heigth and you have 'potential energy' because your just as high. Now the lift drops... down it goes only being slowed by the friction of the elevator shaft and the surrounding air. You are then 'falling at a rate' equal to the pull of gavity and your 'potential energy'. However, since the potential energy of the elevator is greater than your potential energy due to the massive difference in weight, the elevator decends as quicker pace than you will. Thus.. you 'rise' off the floor in much the same way as your feel 'lifted off your seat' when riding a rollar coaster. By the time the lift reaches the bottom you will probably be against the ceiling and then when the bottom of the lift stops.. you won't and will proceed to be 'reintroduced' as a rather high rate of speed. Then the remaing pieces of the lift will then collapse upon you.

Not a pretty picture.. but there's lots of safety devices to prevent this type of problem.

Well.. hope this answers the question!

BTW: The Mythbusters TV show did this exact thing to prove what is described above.

Answer 6

Yes, while you are travelling in the lift you are falling in the same reference frame (IE at the same speed). If you jumped up you would be travelling at the lifts speed minus your velocity of the jump. A split second after the lift hit the ground (and stopped) you would return to the floor of the now stationary lift at speed equally lift speed - minus jump speed plus velocity gained through acceleration (due to gravity).

Other ways of thinking about the same problem would be ; if I jumped up in a train , why don't I fly backwards in mid air ? Or if I stepped off a crashing plane just before I hit wouldn't I be OK?

Answer 7

You would absolutely get hurt. When the lift is falling, you are falling with it and at the same speed as it is. Remeber, it is not the fall, it is the stop that causes injury.

Typically, objects fall at around 180 mph if they are allowed to reach terminal velocity. Even if you could time it perfectly (which is very doubtful) you could not jump up at a fast enough rate to counterract this.

Answer 8

Wow! I've always wondered that! I've spent may hours thinking about it and I think that the answer is yes because you have been falling all the time. I also wonder what would happen if you jump just a little too late would the roof of the lift 'fall' onto your head?! Hmm interesting mind you have...

Answer 9

Yes, but only if you jump up at the right moment...when the lift is at the right...ummm...terminal distance from the surface its gonna hit. Lets say its going down at a speed which requires you to jump up when its exactly X-feet or inches or whatever distance (or when it -for its given speed- it has just x-seconds to hit the ground), if you jump at the required moment, up to the required height in the lift (if it has all the room needed for this evasive leap), you should have enough time/height to miss the crash/impact of the lift as it hits its destination (surface).
Hopefully by the time gravity brings you back down, enough time will have passed for you to have missed the nasty deceleration of the lift. Hmmmm, I hope you're not interested in trying this out in "actual reality" (its definately safer in "virtual reality" a.k.a. your dreams).

Answer 10

By "high enough" I assume you mean fast enough, technically if you can jump faster than the lift is falling, than no you wouldn't be hurt, but chances are it is going really fast, so probably not

Answer 11

Yes, you would be. There is no way a person could jump fast enough to cancel out the speed of the elevator by jumping.