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Old 2009-04-01, 16:37   Link #2694
Asuki-tan Kairin ↓
Join Date: Feb 2004
Location: Fürth (GER)
Age: 37
Originally Posted by -KarumA- View Post
Okay I was sitting in the train letting my imagination running freely while listening to some music, well the thing I started thinking of was teleportation and I started wondering if you fall from a great height (gravity etc. taking effect) and for example you have teleportation abilities and you teleport yourself in water, not above it and then splash but like in the ocean/pool or whatever watery substance may be, what would happen? Would the gravity still have effect or will it be cancelled out or slowed down o.o;
Gravity will be the same... its a rather constant force. What is your concern is kinetic and deformation as well as friction energy.

Lets imagine this scenario to be a little different.
What you describe is basically the same as a large cylinder filled with water falling down and hitting the ground. Lets assume this cylinder is made of a very robust material and does not burst. Lets further assume you are inside the cylinder.

Gravity lets you have potential energy (depending on your distance to the ground/ center of gravity). When falling down (in vacuum) it will be transformed into kinetic energy (in air a part of the energy is transformed into heat through friction).

The inertia impuls when hitting the ground will almost immediately reach you, since water cannot be compressed very well. Thus forwarding the inertia impuls is almost instand.

Anyway, when you/cylinder hit the ground you have a certain amount of kinetic energy. This energy will be transformed into deformation energy and friction energy.

The forces of the deformation energy will be higher the shorter your stopping distance is.
Now since water has a high density, you will be stopped quite fast. But you do not have to break through the surface of the water first. Water at its surface has surface tension, this makes an impact on water very hard (assuming a rather high impact velocity).

Since you are in the water already surface tension is not so much a problem. Still the density of water will slow you down very rapidly. Except you are fast enough for super cavitatation (rather unlikely). If you shoot a bullet from a gun inside water the bullet will be stopped within a few meters (just to get an idea of the stopping power of water).

Anyway, hitting concrete ground will reduce your speed much faster and setting free far more deformation energy, then being stopped inside water. Furthermore the water is all around you, so the forces are better spread over your whole body. When hitting concrete ground the deformating forces will come almost entirely from the direction where the ground is.

So to summarize this, you will be less hurt when slowed down in water instead of hitting conrecte ground (with only air as surrounding medium).
Folding@Home, Team Animesuki
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