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blue_midget192
04-26-2004, 07:55 PM
ok so in all the space/sci-fi type films if gravity is switched off, then all the things in the room start floating! and i was thinking that this wouldn't happen:
example: if a plate is on a table, the plate is being held on the table by gravity right? is the gravity is turned off, then it would not float up because even though there is no gravity to hold it down, there is also no force pushing it up either :) ha? eh? what do ya think of that one!? :D

Kitsune
04-26-2004, 07:57 PM
That's because in Space there is NO gravity.. gravity is created by the spinning a mass on it's axis.. which is why Spacial bodies wuch as Earth, or the other planets have all got different gravities.

crono_logical
04-26-2004, 09:21 PM
That's because in Space there is NO gravity.. gravity is created by the spinning a mass on it's axis.. which is why Spacial bodies wuch as Earth, or the other planets have all got different gravities.That's not quite right. Gravity is present because of mass - the different planets have different gravities because the planets themselves have different masses. If you look at the equation for the force due to gravity in your physics textbook, you'll see the force is proportional to the two masses or objects in question (and inversely proportional to the square of the distance between them). So the planets with more mass are the ones with more gravity.

As for things floating in space in sci-fi films when the gravity generator is turned off, then yes, I'd expect stuff to float :p Why? Because then the only gravity present will be due to the forces between the objects themselves, and they'll all be attracting each other. Yes, there's still a force between the plate and table pulling them together, but the forces between the plate and the entire spaceship and everything else in the spaceship will most likely be greater, and be enough to "unstick" the plate from the table as it were. In fact, I'd probably expect everything to initially float roughly towards the centre of mass of everything present, and so depends on the location of the room to this centre of mass as to whether something will float up or not :p Initially, because things will bounce off each other and start going in other directions, and also as everything is moving, the centre of gravity will also be moving so the force acting upon everything will likely be changing directions too. Plus don't forget gravity due to other objects outside the spaceship - they might be millions of miles away, but if you look at the formula again, you'll see there'll still be a force affecting the spaceship and it's contents, just a very small one :p

Loony BoB
04-26-2004, 09:26 PM
I want to drink floating orange juice. :( That's always been something that I thought would be so cool and fun to do. *deep sigh* Someday...