Quick Descision

[Kingpin1989]

Probably a stupid question...Say a person were on a platform freefalling toward the ground at a high speed. If, at the exact instant before impact, that person were to either push directly opposite the downward force (jumping up) or leapt sideways, would it kill enough speed to keep them alive?

[Ophiolite]

Don't know. Don't want to know. The possibility that it might work is the only thing that persaudes me to get into lifts (aka elevators).

[Guest Corpuscle]

Neither would help him. If the height at which he fell was substantial enough, say 5 floors or higher, even if he were to jump it would cancel only a very small portion of the speed of the fall and then this could also be dangerous because the jump could disorient him before he hits the ground. My best bet is to lay yourself down on the platform because the body can handle more G's that way. Standing up would just flatten you anyway.

[Callipygous]

Probably a stupid question...Say a person were on a platform freefalling toward the ground at a high speed. If, at the exact instant before impact, that person were to either push directly opposite the downward force (jumping up) or leapt sideways, would it kill enough speed to keep them alive?

 

think of it this way, how ever high you can jump is how much force you can cancel, so its just like you fell from that much less height. not much difference...

[blakeja]

The only way you could live would be if the Impact time was large. The Impulse J=Ft=mv shows us that if the time is greater the force of impact will be smaller. An example of this is falling onto a big cushion for example, the cushion "gives" and the time of impact is increased. Makeing you live instead of die

[JaKiri]

The only way you could live would be if the Impact time was large. The Impulse J=Ft=mv shows us that if the time is greater the force of impact will be smaller. An example of this is falling onto a big cushion for example, the cushion "gives" and the time of impact is increased. Makeing you live instead of die

 

Whilst the general post is correct, the maths most definitely isn't. Impulse = Int F dt (which, in simple cases, comes out as Ft), but mv is NOT THE IMPULSE. It is the momentum, and impulse = d(mv)/dt.

[blakeja]

ahh yes thanks for correcting me on that, one of the reasons not to post at 6am after a long night i guess

[YT2095]

Probably a stupid question...Say a person were on a platform freefalling toward the ground at a high speed. If, at the exact instant before impact, that person were to either push directly opposite the downward force (jumping up) or leapt sideways, would it kill enough speed to keep them alive?

sidewys would certainly do nothing, other make you splatter to the left or right of your falling position

 

Jumping UPwards just before landing would help! the platform would have to be considerably more Massive (heavy) that you though, ie/ same weight and the platform moves faster downwards and you that same speed in an upwards direction (you`de halve it).

 

now considering terminal velocity is roughly 200(+ish)Mph, if yiou could accelerate upwards at the same speed as downwards velocity, you`de effectively be at Zero, then you`de just fall from that point again.

personaly, at those speeds, I wouldn`t place my life on the timing of it!

[[Tycho?]]

Probably a stupid question...Say a person were on a platform freefalling toward the ground at a high speed. If, at the exact instant before impact, that person were to either push directly opposite the downward force (jumping up) or leapt sideways, would it kill enough speed to keep them alive?

 

Depends on how high you fall from.

[YT2095]

yes and no, you DO accelerate but only up to terminal velocity, then it levels off.

so after a certain height, any extra is irrelevant

[Callipygous]

if terminal velocity is 200 mph... lets say you can jump 3 feet in the air, a bit of a stretch for most people.

 

P=vt -16t^2

p=3 feet halfway through the jump

 

time to fall 3 feet:

3=16t^2

sqrt(3)/4=t

 

3=v(sqrt(3)/4)-16(3/16)

3=v(sqrt(3)/4)-3

6=v(sqrt(3)/4)

v=1.5sqrt(3) ft/sec

v=2.598 ft/sec= 1.771 mph

 

so instead of hitting at 200mph you will hit at 198.229mph.

 

hows my physics? its been a few years...