Questions about physics, especially gravity and electromagnetism

[Zeblote]

magnets

obviously not a perpetual motion machine, actually would act as a very weak mechanical generator

But how the hell does that thing rotate on it's own
And it even speeds up

[Ad Bot]

[Kearn]

1. instead of complaining about what words I used or whatever you're doing, answer the question
2. first of all, an electric pump wouldn't even use all the energy that a gas generator creates. that's ridiculous. and besides that, you could always do it the old way, and use a manual pump

1. i'm not complaining, weight is irrelevant in 0g and pretty much irrelevant in general because something will weigh more on jupiter than the moon but ok mass less mass is easier to move because there's fewer atoms to transfer velocity to
2. lost me

[Siren]

(I think, i may be wrong) but gravity works due to how mass effects space-time, it basically means if everything is on a flat plane (a tabletop for example), the bigger the mass, the bigger the hole it makes on the plane, so a ball would roll towards a big hole (the earth or whatnot). Squares wouldnt roll but were talking about no atmosphere so it would still apply.

Again, not sure if this is true but it makes sense to me

[Night Fox]

1. i'm not complaining, weight is irrelevant in 0g and pretty much irrelevant in general because something will weigh more on jupiter than the moon but ok mass less mass is easier to move because there's fewer atoms to transfer velocity to
2. lost me

weight is not irrelevant. on earth you have it, but in space you don't, and that makes a difference in how much energy it takes to move. since I'm talking about the energy it takes to move something in space compared to how much it takes in gravity, it's relevant. but it still doesn't make sense to me. there's nothing resisting the movement. so why would it take more energy to accelerate

how did I lose you with that?

[Siren]

Ignore this misread question

[Night Fox]

ok nevermind then

[Cool Boi]

Energy comes from the earth's core.

No, energy comes from the Chaos emeralds.

[keesfani]

newton's first law

[Night Fox]

newton's first law

what are you trying to answer

[hgpucom]

The answer to all your questions is Mass. There is no gravity in space but mass effects everything.

[Oasis]

Since this is a physics thread this is perfect
Can someone explain to me how this works
http://www.youtube.com/watch?feature=player_detailpage&v=oJv58SXx2V8#t=159s

Oh my god those videos are hilarious.

The Man is keeping free electricity down so they can make money!

[Kalphiter]

ok, first is like
for orbit, and every other kind of movement in space, where does all the energy come from? like, we're always moving through space, but the earth isn't putting out. I don't understand! no energy is required for orbit, besides what gets you there in the first place, right? so why do you keep moving? it seems like cheating. as soon as you're done accelerating, there's no issue of power. but why not?!

The earth is already in orbital motion and its speed balances (on average) with the sun's gravitational force. I have no idea what caused pieces of the earth to first move but it's probably related to how it was created. The solar system was at first a nebula, in which gases attracted each other by gravity into planets and the sun, with the sun being the densest of them all. This entire gas cloud was spinning around the central mass (what became a star) and that's how certain dense fragments (planets) started orbiting the sun.

second: does mass affect the speed of acceleration in zero-gravity? like, a baseball and a car with the same engine, would there be any difference in the amount of energy required to get them to the same speed?

Zero gravity just means there is no overall force on the object. It would be harder to push a car in zero gravity than it is to push a baseball.

third: if you have a generator, and you're in zero-gravity, and you get it going, would it require less power to keep it going than it would on earth? since there's no gravity, there'd be a little less resistance, right?

I imagine what would happen is that frictional forces incurred would end up being always even instead of lopsided because gravity is in one direction.

fourth: speaking of generators... this one is a little hard to explain. but imagine a really large, circular tube surrounding the earth way up in orbit. the tube isn't (necessarily) turning, unless it would need to. but there's a big magnet moving in orbit, through the tube, and the inside of the tube is like, a really really long coil of wire (whatever kind of wire would allow for electromagnetic induction. like in generators). or the tube could be the magnet and the orbiting thing could be the wire coil, but I doubt that would be as effective. so, what I'm asking is, would that work to generate electricity? like, I'm sure it's not feasible right now, and it would be very expensive, I'm sure, but it is possible?

The problem here is that you have to somehow get this humongous ring moving. There's no such thing as a free lunch.

[Zeblote]

Oh my god those videos are hilarious.

The Man is keeping free electricity down so they can make money!

You are supposed to tell me how it works not make a useless comment!!!!!

[Nickelob Ultra]

ok, first is like
for orbit, and every other kind of movement in space, where does all the energy come from? like, we're always moving through space, but the earth isn't putting out. I don't understand! no energy is required for orbit, besides what gets you there in the first place, right? so why do you keep moving? it seems like cheating. as soon as you're done accelerating, there's no issue of power. but why not?!

second: does mass affect the speed of acceleration in zero-gravity? like, a baseball and a car with the same engine, would there be any difference in the amount of energy required to get them to the same speed?

third: if you have a generator, and you're in zero-gravity, and you get it going, would it require less power to keep it going than it would on earth? since there's no gravity, there'd be a little less resistance, right?

fourth: speaking of generators... this one is a little hard to explain. but imagine a really large, circular tube surrounding the earth way up in orbit. the tube isn't (necessarily) turning, unless it would need to. but there's a big magnet moving in orbit, through the tube, and the inside of the tube is like, a really really long coil of wire (whatever kind of wire would allow for electromagnetic induction. like in generators). or the tube could be the magnet and the orbiting thing could be the wire coil, but I doubt that would be as effective. so, what I'm asking is, would that work to generate electricity? like, I'm sure it's not feasible right now, and it would be very expensive, I'm sure, but it is possible?

I probably seem stupid asking these questions. but I'm curious. and I can't ask my teacher, because he's not actually knowledgeable about it, he's just a baseball coach that the school got to teach a class because they didn't have enough teachers or couldn't afford to pay enough teachers idk

1.  Regarding orbit, you must first understand some basic concepts of physics:

• An object in motion will remain in motion and an object at rest will remain at rest unless acted upon by a force.
• Space is a vacuum.  There are no particles in space, things like asteroids and space ships will not "slow down" after moving because there is nothing that is stopping them as opposed to air resistance/gravity/friction on the Earth's surface.

Now that we have these concepts laid out, check out this diagram gif:

a is the acceleration towards Earth due to gravity.  Gravity still affects distant objects in space, including the Moon.  This is why satellites don't just drift off.
v is the ongoing, unaffected velocity of the object (black sphere going around the Earth).  Because the object is in space (a vacuum), there are no forces to act upon it except the force of gravity ( a ).  And because there are no forces to act on it, it will keep that speed.  Because it's keeping the same speed and is still affected by gravity, it moves in a nice circular orbit.

Ta-Da, you have now discovered what orbit is!  For more hands-on application, check out the indie game Osmos on Steam and play some of its orbital levels.

2.  This is a good question, and I don't know the answer for sure, but my best guess would be no, mass wouldn't affect acceleration speeds in zero gravity.  It would require less power to make it move because like I said earlier, things in space will just keep going and going infinitely.

3.  I'm not sure what the thinking is here, but I don't think it'd require less force assuming you're talking about some kind of hand crank magic.

4.  If there was a big magnet running around the Earth in an orbit it would likely forget up a lot of things and wouldn't do much really.