# Physics???

I just have a couple of Questions if anyone knows

1. Why is potential energy Not energy due to gravity?
for one the formula is H x G x M = potential energy (hight gravity mass)
Couldent you replace the gravity with another force, such as magnetism.

2.In Einsitens theory of reletivity the Mass of the sun should BEND the space around it, WHAT THE HELL IS IT BENDING??? space is a friggin vacum :o THERES NOTHING THERE TO BEND!!! (let me guess its bending time and space itself %| ) that reminds me, i dont belive in “Time” the way Einstine talks about it, he talks about it like its somekind of time line that if we do somthing we can unlock a Key to the past (time travel). I think it works like this… atoms move… there not recorded in some kind of TIME database like Einstines theory suggests.

O…K…this is the most ive ever typed.

1. Of course, potential energy also exist with electromagnetic forces and every other force that exists.

2. The sun doesn’t bend what’s in space, it bends the space itselfs, it bends the space “geometry”. If you want to go straight in a 'bended space" you would turn.

If you draw something on a paper sheet, you can bend it, and straight lines wouldn’t be straight anymore, but even if the sheet is empty, you can still bend it. You can see “space” as the support of matter as the paper sheet is the support of ink.

as you guessed it bends space and time. time goes a little slower around heavy objects because of the deformation of space and time.

Think of space as water and fish as planets, stars, whatnot.

1. As above

2. Time isn’t quite as you put it. In General Relativity (and Special) time is dealt with in the same way as the three dimensional co-ordinates, this is required in order that the laws of physics remain the same no matter how fast your frame of reference is moving. However whereas we are free to move in the spatial dimensions we are constrained to be drawn along in time.

One of the fundamentals of GR is that there is no yardstick like you describe. You can only define intervals (a distance in space and time) between “events” such as two particles meeting. Using these events we can apply a co-ordinate system (like on a map) with the events being like the towns. Take away the co-ordinates and the towns remain, so it is with events. Thus any mapping of time relies on events, not a fixed scale like you described it.

Hope that helps.

Alex

Edit: note that GR and the curvature of space-time explain measurements that do not keep with Newtonian mechanics, such as the exact value of the precession of mercuries orbit.

1. Thats what i thought but someone told me different.

2. the timeline thing i was talking about was that some people say that events are “remembered” like we can go back and redo them.

i didnt say that i was just asking what it was Bending, how could it bend some things and not others (your saying it bends Existance itself but not the earth?) where does this bending begin, mass-wise.

Thanks for the help by the way.

A vacuum isnt empty its a mass of virtual particles winking in and out of existence. This is known from quantum theory and heisenberg uncertainity principle. The vacuum has a certain energy called the zero point energy.

Its the theory of general relativity that shows how space and time curves about a massive object. When light curves about a massive object it is actually following the shortest route about that object. General relativity is a mathematical theory and you have to know all sorts of things about mathematics such as tensors and calculus to understand why in Einstein theories space can be curved. However, there is a simple analogy, which kind of illustrates what is going on. If space was 2 D and like a rubber sheet and you placed something heavy on this sheet then the rubber sheet would form an indentation. 3-D space is a similar rubbrey medium and deforms about objects.

As for potential energy as the name suggests its only potential. Lots of different types. A battery has potential energy, its stored in the chemical strucutre of the battery. Its only used when you have some sort of resistance across the + and - terminals. When you drop something the potential energy that is the stored in the object depends on the height and weight, but you are right we could call this gravitational potential energy, and the energy stored in a battery we could call chemical potential energy, but it both are forms of potential energy.

not to sound mean, but there are these wonderful places called libraries which happen to be full of books. there is this one book in particular that i would suggest getting and it is called “blackholes wormholes and time travel”. tis a very interresting book that the author has put in layman terms very nicely. if you want a good grasp on stuff like this you are either gonna have to take a class on it, or read a book or 2 on it.

Simply put, it bends everything. Anything with mass has a gravitational force which affects the surrounding space (i.e. space-time). The degree of bending diminishes with distance, but never stops. All things are affected by the sun’s gravity.

An example is that time moves more slowly on Earth than in orbit–a fact that must be taken in account when synchronizing with (man-made) satelites. GPS works by taking advantage of this fact.

We don’t notice it because we’re being “bent” too. Ever see the Futurama episode where the professor creates a box with the universe inside? At the end Fry sits on the box and everything is scrunched but no-one notices?

Same difference. The only way we know of the bending is by careful observation. For example, we know light is bent around a star because we can observe starlight being bent around the sun as time passes.

AFAIK, only tachyons travel backwards in time… we can’t. However, we can see things in the past. One common example is starlight. What you see is millions and billions of years long gone. There might be other ways too, but here my meager knowledge ends.

I hope this helps.

Potential energy is simply the energy available in an object that is not doing work, but could be converted to kinetic energy (work). The keyword is potential. Potential energy, thus, is somewhat relative. In the case of masses or physical object at the size that we normally handle them, potential energy is usually a result of gravity. The higher it is, the farther it can drop so the more it can move and accelerate if dropped. The result is that more potential energy can be converted to work (kinetic) energy. Now, potential energy doesn’t have to be gravity. It can be created by, as -efbie- said, electromagnetic forces as well as other forces, although, these are usually refered to as working forces I think.

A common area you will find non-gravity caused potential energy is in chemical kinetics. In this case an exothermic, spontaneous reaction will normally have a starting potential energy. The reaction will convert the potential energy into kinetic energy which results in the reaction going to completion (which has a lower potential energy which is why the reaction won’t spontaneously go back the other direction; unless it is an equilibrium reaction). In this case, gravity is not involved at all but the reaction process is monitored by the amount of potential energy in the molocules in the reaction.

The formula you gave is only for determining potential energy for certain situations, but other formulas exist for other situations. You couldn’t just simply replace gravity with another type of potential energy source in that equations.

Enough rambling.

Cool, but 1) Were do these particles come from and 2) frig YOUR MEAN Just kidding

The particles are actually particle - antiparticle pairs. To produce them requires energy. Luckily the ‘void’ is also filled with billions upon trillions of massless, extremely weakly interacting neutrinos. Then there are the photons (which must be there in vast numbers or we wouldn’t see anything). These have anything up to 20 Joules each (yes 20 Joules, the amount of energy required to lift a kilo 20m against 1g! (OK, these VHECR are rare, but exist)).

Also, did you know that neutrons are not stable particles? If not bound in a nucleus a neutron will decay with an average lifetime of 15 minutes!

Alex

Cool, but 1) Were do these particles come from[/quote]

This is to do with Heisenbery uncertainity principle, which in one form is a relationship between energy and time. So as long as the pair of particles exist for a very small amount of time then they can form out of nothing. That these particles form gives the vacuum a small amount of energy (zero point energy) which can be measured.

what happens “theoreticaly” if you remove all the energy from a place, It might not be possible but what if?? and how can a neutron split and become a proton and netron but a proton splits to become a neutron and positron??? is this false information?? (or did the book say photon???)

The more precisely the position is determined, the less precisely the momentum is known in this instant, and vice versa. Can someone tell me what this means?

And frig my library sucks @\$\$

Yep, that info is false.

What uncertainty means is that if I know that my position is within deltaX of the real position and I measure the momentum I can only get it accurate to deltaP of the momentum of the particle where:

deltaX times deltaP is greater than or equal to Planck constant/ 4 pi

Alex

Cool but I cant undersand EVERYTHING that your saying though, im only in 9th Grade, but i understand some, to most, of it.