Gravity is a singularity? Help me out...

[Everten P.]

So I was lookin on the Internet and I saw a perpetual motion device (look on YouTube you will find at least one) and I looked like it worked, the only thing was it had to be pushed. Now according to the 2nd law of thermodynamics that can't be possible. But theoretically could gravity be a force cause by atoms.. radiating? If energy cant be removed or put in the universe could the force of gravity be atoms being ripped apart to pull others toward them? HELP I AM COMFUSED:confused:

[Dodgey]

Can you link the video in question? Technically gravity is caused by things having energy and momentum (light included). But can you rephrase your last sentence, you have me confused with that.

[Tex]

Well, my first impression is that it's just a hoax like all of the other "perpetual motion" devices ever invented. You've even disproved it's perpetualness yourself:

the only thing was it had to be pushed.

That right there means you need to push it for it to work at all, correct?

[Everten P.]

Pushed once and type top ten perpetual motion machines of 2013.

[xcorps]

Pushed once and type top ten perpetual motion machines of 2013.

There is no such thing as a perpetual motion machine. Typing "TOP 10 Perpetual motion machines of 2013" is like having an operation to change gender. It only looks like it.

[Dodgey]

Here is a video explaining the concept of gravity. What make out of those 10 machines are you talking about? And can you please explain what you mean by atoms bring ripped apart?

[Accelerando]

There is no such thing as a perpetual motion machine. Typing "TOP 10 Perpetual motion machines of 2013" is like having an operation to change gender. It only looks like it.

chromosomal ***, yes. gender, no.

i've always been curious about gravity too, i assumed since you need to expend energy to fight it then it must require some energy itself to exert. this is not the case, yeah?

edit: i can't believe that a basic function of human beings and the name of a basic human concept is a censored word on these forums. going all the way with the parent-friendly status, i guess...

[Dodgey]

i've always been curious about gravity too, i assumed since you need to expend energy to fight it then it must require some energy itself to exert. this is not the case, yeah?

As I understand it yes. The potential energy comes from the distance between the two objects. I think that was the question you were asking, correct?

[KerbMav]

As I understand it yes. The potential energy comes from the distance between the two objects. I think that was the question you were asking, correct?

What came first, the potential energy or gravity?

[Sirrobert]

Potential energy does not exist.

It is simly a way for us to calculate how much energy could be exerted by gravity / is required to fight gravity

[Dodgey]

The potential energy in that sense could not exist without gravity, though that question is like asking what came first, time or the universe.

Edit

Darn ninja. Yea that is true, it's a concept, which is why I compared it to my other question.

[Sirrobert]

Because potential energy is simply a mathemetical construct, gravity came first

[phoenix_ca]

Perpetual motion machines cannot exist. Every single physical process we know about has some inefficiency in it, be it friction, or the small amount of heat generated by a loss of kinetic energy when a bouncy ball compresses, or aerodynamic drag, or heat generation from metal fatigue, or...okay that's enough. Point made. If you could get away with some amazing breaking-the-laws-of-physics-as-we-know-them thing then sure, maybe. Probably not.

Gravity is the result of matter distorting space-time. Pretty much all matter does it to some degree just by existing. There are some theories that postulate that gravity may be mediated by a particle (just as light is mediated by photons), but so far there is no experimental evidence for this view.

[YNM]

could gravity be a force cause by atoms.. radiating?

That would be black-body radiation, in which, instead of keeping the energy, radiates them (approximately) evenly to all direction (so to all part of the observable Universe eventually). Also, the fact that photons can actually push things around instead of attracts them...

[Lukaszenko]

i've always been curious about gravity too, i assumed since you need to expend energy to fight it then it must require some energy itself to exert. this is not the case, yeah?

You don't need energy to fight gravity. You can rest a book on a table and it will sit there for as long as we please, fighting gravity, with no energy expenditure. You only need energy when you exert a force over a distance, but a force standing still, no matter how large, requires no energy.

As for gravity being atoms ripped apart, as far as I know there is no scientifically accepted theory that would agree with this, so it's safe to say "no" unless there can be provided some much deeper explanation backed up with math.

[Sirrobert]

You don't need energy to fight gravity. You can rest a book on a table and it will sit there for as long as we please, fighting gravity, with no energy expenditure. You only need energy when you exert a force over a distance, but a force standing still, no matter how large, requires no energy.

As for gravity being atoms ripped apart, as far as I know there is no scientifically accepted theory that would agree with this, so it's safe to say "no" unless there can be provided some much deeper explanation backed up with math.

Not really.

The table is exerting an equal but opposite force. It's just that this force is the material resisting change, and thus you could count it as not exerting any force. But it is still working against gravity.

There is always either an equal but opposite force (in which the object in question stays in place), or that opposite force is missing (you relase the book in mid air), and than the forces that do apply accelerate it along their vector

[ZetaX]

No, Lukaszenko is completely right. Energy is force times (or integrated over) distance. If something does not move, there is no energy excerted, as he said. Energy is released or used up if the potential changes, that's all. Otherwise stable orbits would not exist, too.

Newton's Law of inertia is not directly related to this, as force is not work/energy.

[TheGatesofLogic]

Not really.

The table is exerting an equal but opposite force. It's just that this force is the material resisting change, and thus you could count it as not exerting any force. But it is still working against gravity.

There is always either an equal but opposite force (in which the object in question stays in place), or that opposite force is missing (you relase the book in mid air), and than the forces that do apply accelerate it along their vector

That's not right. Energy can formulated by finding the area under a force curve with respect to distance (equivalent to a constant force multiplied by the distance over which it acts) and in the case of an object sitting on a table you have an electrostatic force that repels the physical object and the physical table that results from the charges and distribution of those charges in the structure of materials at the atomic and nuclear level, but this repulsion is in equilibrium with gravity by pulling the materials close enough together that the repulsive force between them equals the force of gravity and forms a stable state of equilibrium. In this state of equilibrium the sources of the forces do not move relative to one another and hence there is no* energy input or output. (Nothing is truly physical as we like to think, physical contact is not REALLY possible as we think of it, however the weak force, which has nothing to do with this, can be interpreted as having a finite range which leads to some interesting effects that you may learn about later on in your life)

I will however concede that it might be best to interpret the statement by Lukaszenko saying, "you don't need energy to fight gravity" as "you don't need energy to fight gravity in some circumstances, but you do in others" since energy IS required to lift an object against gravity from one height to another.

*(more complicated stuff makes this statement somewhat untrue)

[phoenix_ca]

the weak force...leads to some interesting effects

Sub-atomic forces do weird and wonderful things, it's true. (I love the standard model. It's so damn pretty.)