A question that has been bugging me.

[chazus]

A parachuter has a parachute to slow their descent though :P Just bouncing them sideways won't cut it. If it was at an angle that also introduced an upward force it might work though.

Parachuters still come down at a fairly decent speed. You'll almost never see a parachuter come straight down. It's always at an angle, and a run. There's a reason for that.

And the angle of the trampoline provides the upward force... Though, it would have to be a particular trampoline, so as not to still injure him on the bounce (And also a perfect landing on it too)

[Tradewind]

Parachuters still come down at a fairly decent speed. You'll almost never see a parachuter come straight down. It's always at an angle, and a run. There's a reason for that.

And the angle of the trampoline provides the upward force... Though, it would have to be a particular trampoline, so as not to still injure him on the bounce (And also a perfect landing on it too)

Well yes, it's definitely less of a shock on the limbs to come down on an angle. But the deceleration is the important part. If a parachutist came in on an angle at terminal velocity, they're still going to turn into red paste lol. You'll just maintain your momentum into a slide. Think of a meteor

Unless I'm not understanding what you mean by the angle of the trampoline.

[chazus]

I just figure if he survives the trampoline bounce (even a bounce at an angle is a pretty violent change in velocity. In theory it would get him moving horizontally at the same speed, allowing him to (through amazing dexterity) manage to catch himself on his feet with a hop, skip, run, and slowly getting to a stop, or at the very least a roll. Worst case, he simply takes a nose dive, but moving at (I didn't do the math, but terminal velocity of a person falling is ~120mph), about 70mph and 'tripping' is certainly more survivable than hitting straight down. People on motorcycles with some leather gear have certainly survived it.

[Tradewind]

I just figure if he survives the trampoline bounce (even a bounce at an angle is a pretty violent change in velocity. In theory it would get him moving horizontally at the same speed, allowing him to (through amazing dexterity) manage to catch himself on his feet with a hop, skip, run, and slowly getting to a stop, or at the very least a roll. Worst case, he simply takes a nose dive, but moving at (I didn't do the math, but terminal velocity of a person falling is ~120mph), about 70mph and 'tripping' is certainly more survivable than hitting straight down. People on motorcycles with some leather gear have certainly survived it.

It'd have to be at an angle much less than 90 degrees. They'd be falling at roughly 44 feet/sec, about 30mph by the time they hit the ground. Any kind of lateral force changing their trajectory would just displace their landing position relative to how much force you exerted against them. Without any kind of deceleration they'd still be hitting the ground at ~30mph. It would have to slow their vertical velocity somehow and in some significant way, hence an upward or resistant force of some kind applied in counter to gravity.

Conservation of Momentum. The variable is whether or not it's an elastic or inelastic collision. Hitting a trampoline would be an elastic collision where kinetic energy is transferred in another direction. Inelastic would be hitting the ground, where the kinetic energy is lost. In this example, it's lost in the form of his legs blasting apart.

[chazus]

Well, I'm sort of using a... "Theoretical" trampoline. I'm pretty sure any normal trampoline that caught someone moving that fast would either break, or not provide enough elastic conversion and simply injure/kill while ejecting him to the side.

GRANTED, there are safety trampolines for exactly this thing. If one were set up at an angle, for him to intentionally jump down on, and with proper skill land on his back and not his legs, I think it would be survivable. It would likely need to be at about a 30 degree angle.

[Tradewind]

Physics is fun

[glycerethe]

At times like this, you just have to tell him "Cheryl Cole is behind him, NAKED."

[Zangeiti]

If I have learned anything from video games it that physics is weird. And In Gmod or any messed up physics game like kerbel space program you'd probably just kill him

[SodiumChloride]

No. You will just accelerate him slide ways away from you. There is no change to his downward velocity.

[Dezerte]

Having not studied physics any higher than "högstadiet"-level, simply pushing the falling object exactly sideways would not affect the downward velocity. It might affect it a tiny tiny bit seeing as the Earth is not flat, and by pushing the object sideways you would actually create a very tiny upwards force but I'm not sure how quantifiable that is.

[Aleksej89]

In short, it does not really matter how the falling friend comes to a stop from that falling distance - it can be a collision with a floor, with you, with a car or whatever else... at that speed (gravity and falling distance) the sudden stop of the force building up from falling would be enough to cause fatal injuries.

As morbid as it sounds, you are better off not having your car (or yourself) damaged, since that falling person is most definitely dead on any impact - only way to save him would be to slow down his descent over time so it is not a bone crushing stop.

As some smart sciency dude said: it is not the fall that kills you - it is the sudden stop.

[Deleted]

I have no idea about physics so I'' give you what common sense tells me.

No.

[TheNationGamer]

you should try it and post the results

[sugarlily]

I see your devious but brilliant plan. He will most likely put you in his will for this!
It reminds me of the old "SAVED YER LIFE!" trick.

Do kids still do that?

I'm old >.>
get off my lawn

[Stir]

As others have said, the downward velocity is not altered by adding a lateral component.

So the only way to stop your friend's downward velocity is to apply upwards velocity that is equal to, or greater than, your friend's downward velocity. Assuming you have no tools to aid you in this, the force would be applied through the means of a clenched fist.
So you'd have to add a force great enough to lift your friend's body (making it defy gravity) and at the same time be greater than the force generated through the downward velocity of your friend's body falling thirty foot.

Depending on where you touch your friend, be it sternum or abdomen, your fist may well penetrate your friend's body and come out on the other end. In the process, severe damage may be done to your spine, since the falling body is an active component rather than a stable one (it enacts great force on your body, rather than, if the falling body were stationary, your body only affecting the falling body without reciprocating force). If you try any other method than a strike (with a clenched first), you'll likely suffer great trauma, and may not even survive.

All in all, both your own chances and those of your friend are better if you simply let them hit the ground.

Edit: As for the angle of the parachitist: This is to lose velocity when already touching the ground. Running/rolling it off. An angle is required, because you cannot roll/run off your speed straight down into the ground.

[Deleted]

You would have to push him with enough force to alter his downward descent. A human doesn't have the capability to do that. Now, if he fell off, and you were driving a car at say... 40mph, and hit him just before he hit the ground, yes, you'd break his 'fall'. You'd also kill him in the process by changing his direction and speed so violently.

Short answer: No, you cannot push him and break his fall
Long answer: His fall CAN be broken by having him 'pushed' by something, but it would likely be more damaging than the fall itself to do so.

Yeah, being hit with that much force would be a pretty bad thing. All that energy has to go somewhere, it can't suddenly vanish. Even catching him if you could do so would quite likely not help much.

[lokii]

Not one bit. Think of firing a bullet. Fire it at someone's head with no gravity. Now fire it with gravity which causes it to hit the person in the foot. The bullet will hit the person with the same force in either scenario, just in different locations.

[SodiumChloride]

As others have said, the downward velocity is not altered by adding a lateral component.

So the only way to stop your friend's downward velocity is to apply upwards velocity that is equal to, or greater than, your friend's downward velocity. Assuming you have no tools to aid you in this, the force would be applied through the means of a clenched fist.
So you'd have to add a force great enough to lift your friend's body (making it defy gravity) and at the same time be greater than the force generated through the downward velocity of your friend's body falling thirty foot.

Depending on where you touch your friend, be it sternum or abdomen, your fist may well penetrate your friend's body and come out on the other end. In the process, severe damage may be done to your spine, since the falling body is an active component rather than a stable one (it enacts great force on your body, rather than, if the falling body were stationary, your body only affecting the falling body without reciprocating force). If you try any other method than a strike (with a clenched first), you'll likely suffer great trauma, and may not even survive.

All in all, both your own chances and those of your friend are better if you simply let them hit the ground.

Edit: As for the angle of the parachitist: This is to lose velocity when already touching the ground. Running/rolling it off. An angle is required, because you cannot roll/run off your speed straight down into the ground.

To be more specific, what you need to apply is an upward force - preferable a low one over a period of time that causes him to slowly decelerate without breaking his bones; the alternative is to let him hit the floor, which will generate a (huge) force alright - Newton's 2nd law - and cause him to decelerate very very quickly killing him.

[Stir]

To be more specific, what you need to apply is an upward force - preferable a low one over a period of time that causes him to slowly decelerate without breaking his bones; the alternative is to let him hit the floor, which will generate a (huge) force alright - Newton's 2nd law - and cause him to decelerate very very quickly killing him.

Of course, applying such force slowly is an option... However, the human body is simply not tall enough to provide such a slow build-up of force.