Understanding Work and Energy Transfer: The Relationship and Implications

[JoeWade]

i said it using smaller words

 

[rayjohn01]

Beatrix
If the distance between them increases ( which I am told it does ) and their masses do not change , then their center of mass does not change but the force of gravity decreases ( between them ) , to balance this the common( and opposite) centifugal force must decrease which means both orbital velocities decrease wrt their center of mass. Since the mass of the Earth is much greater than the moon it's orbital velocity is much smaller but the percentage changes to each are the same and equal to half the percentage change of the distance.

 

[Alkatran]

Here's what you're having trouble understanding:

The velocity never changes. The distance between the two objects never changes.

Now, notice that energy is NOT a vector. This means that a change in direction WILL NOT CHANGE ENERGY AT ALL. You can rotate the speed all you want, you have the same kinetic energy.

Now, you also need to understand that there are different 'types' of energy and they are calculated differently. For example, kinetic energy is calculated via the equation you've already given: d*F = Ek. However, potential gravity is another type of energy and has a different equation associated to it: d*F=Eg.

Oh wait! They're the same thing! or are they?
The distance in the kinetic energy is distance TRAVELLED. The distance in the potential gravity equation is the distance BETWEEN two objects.

Since (assuming circular orbit) the moon is not changing speed, its kinetic energy is unchanging, so we can calculate the potential gravity change:
Since the moon is the same distance from the Earth on both sides, and the same force is (generally) being exerted on it, potential gravity is conserved as well.

Now, since the orbit is actually elliptical, and potential gravity energy drops as the moon approaches earth, this energy needs to go somewhere. It ends up as kinetic energy, making the moon move faster as it approaches earth, and, therefore, moving slower as it recedes.


Understand?

 

[beatrix kiddo]

it's ok, tran.. my post was old...

Now, since the orbit is actually elliptical, and potential gravity energy drops as the moon approaches earth, this energy needs to go somewhere. It ends up as kinetic energy, making the moon move faster as it approaches earth, and, therefore, moving slower as it recedes.


Understand?

yeah.. that's why i didn't do a follow up post...

Now, notice that energy is NOT a vector. This means that a change in direction WILL NOT CHANGE ENERGY AT ALL. You can rotate the speed all you want, you have the same kinetic energy.

u really, REALLY don't have to tell me energy isn't a vector..

 

[Alkatran]

it's ok, tran.. my post was old...
yeah.. that's why i didn't do a follow up post...
u really, REALLY don't have to tell me energy isn't a vector..

I wasn't arguing specifically towards you, more along the lines of this:

Yes, temperature is a measure of heat. Sorry for that. There is a required source of energy to exert work on an object. Energy is related to force. We've established that through a poorly derived equation. I'm sure a little more work we can get a nice relationship.

If a magnet is said to do no work, how is that possible? We know it requires a force to act against gravity to stay on the refrigerator, but no work is done, because it doesn't move anything. In examples ithat nvolved pushing stuff, the energy is transferred into heat, if nothing is moved. What is the case with the magnet?

Because electromagnetic forces are calculated in the same way gravity is, the same "different energy" argument applies. However, as was already stated, the force/work/energy/I'm really not sure, not my area from gravity is spread through the molecular bonds in the atoms that the magnet is 'latching' onto. (right?)

 

[urtalkinstupid]

Force is related to Energy, Force is related with work, so Energy and Work are related.

I was not saying energy was a vector that can be applied in a direction. The energy is spread out (scalar), while force is applicable in a direction vector). Are you trying to tell me that work is not scalar, so I can't relate Energy to it, because it contains a vector? I'm not getting it.

 

[Chronos]

Alkatran has it right, as does chroot. You don't need an energy supply if no work is being done. Force and energy are not the same thing. Energy is conserved, force is not.

 

[Alkatran]

Force is related to Energy, Force is related with work, so Energy and Work are related.

I was not saying energy was a vector that can be applied in a direction. The energy is spread out (scalar), while force is applicable in a direction vector). Are you trying to tell me that work is not scalar, so I can't relate Energy to it, because it contains a vector? I'm not getting it.

I'm not exactly sure how to explain this to you, because you have a history of misinterpreting explanations. But let's just say that whatever it is that gets rid of the vector part of a force is the multiplication by distance.

You can't add vectors to scalar quantities, so if work isn't scalar you can't add it to energy... and we do. So.. work is scalar.

 

[urtalkinstupid]

You can convert scalar to vector and vice versa.

 

[Chronos]

You can convert scalar to vector and vice versa.

I will try to refrain from getting sucked into arguing against your flawed theories and the precious little math you use, but clearly do not understand, to support them.

 

[russ_watters]

This is as far as I got in the thread and it bears repeating:

This is not difficult to understand.

- Warren

This is not difficult to understand. I'm no longer amused and I no longer believe there is any chance you kiddies are making an honest effort here.

 

[beatrix kiddo]

chronos u can convert from scalar to vector.. and russ we aren't trying to amuse u..

 

[Math Is Hard]

chronos u can convert from scalar to vector.. and russ we aren't trying to amuse u..

why would you do that? I am not sure I follow...? For instance, if you take away the directional component of a force and only have a magnitude of acceleration (times mass) remaining, doesn't that leave you with a push or pull in no direction?

But maybe I don't understand what you mean by "convert".

 

[Alkatran]

why would you do that? I am not sure I follow...? For instance, if you take away the directional component of a force and only have a magnitude of acceleration (times mass) remaining, doesn't that leave you with a push or pull in no direction?

But maybe I don't understand what you mean by "convert".

When you use the work equation, you multiply by sin(A), which breaks it down to one of the components of the vector. This component is scalar. (You do it all the time when summing vectors)

In essence, multiplying by a trig function tends to remove the vectoriel properties of a vector.

To Urtalkinstupid:
My mistake, it's the multiplication by the angle, not the distance, which makes Work scalar.

 

[russ_watters]

...and russ we aren't trying to amuse u..

No, you're probably just trying to amuse yourselves. Regardelss, the only reason you two are still members here is you are amusing to us (except a small possibility others are learning from your mistakes). Our patience, however, has limits.

The concept being explained here is (again) junior high science class simple (and I'm pretty sure I could make an average elementary school student understand it*). Its simply not possible for you two to not be smart enough to understand it. That means you guys are choosing to not understand it. Why, we're not sure, but regardless, you are not making an effort to help yourselves and you are not making a positive contribtion to this board.

*Elementary school analogy: A car stationary at idle does no useful work. All of the energy input by the engine is wasted as heat, either dissipated by the radiator/engine block or blown out the tailpipe.

 

[jcsd]

You can convert scalar to vector and vice versa.

You can get a scalar from a vector (by taking the modulus for example), but you can't get a vector from a scalr without introducing another vector.

 

[beatrix kiddo]

No, you're probably just trying to amuse yourselves. Regardelss, the only reason you two are still members here is you are amusing to us (except a small possibility others are learning from your mistakes). Our patience, however, has limits.

basically u see stupid and me as a couple of clowns here for ur enjoyment... and ur patience is limited... what's going to happen when it runs out? are u going to close this thread down, too?

Its simply not possible for you two to not be smart enough to understand it. That means you guys are choosing to not understand it. Why, we're not sure, but regardless, you are not making an effort to help yourselves and you are not making a positive contribtion to this board.

we choose not to understand?! oh we understand.. we ALL understand...

*Elementary school analogy: A car stationary at idle does no useful work. All of the energy input by the engine is wasted as heat, either dissipated by the radiator/engine block or blown out the tailpipe.

...

You can get a scalar from a vector (by taking the modulus for example), but you can't get a vector from a scalr without introducing another vector.

agreed

 

[Entropy]

so Energy and Work are related.

Work and energy are the same thing.

E = {{kg} \cdot {m^2}} / {s^2}

W = F \cdot m

and...

F = {{kg} \cdot {m}} / {s^2}

so substitute F and you get...

W = {{kg} \cdot {m}} / {s^2} \cdot m =

{{kg} \cdot {m^2}} / {s^2} = E

Therefore...

E = W

 

[Alkatran]

You can get a scalar from a vector (by taking the modulus for example), but you can't get a vector from a scalr without introducing another vector.

You use two scalar values and an angle to get a vector. (Unless the components of a vector aren't considered scalar?)

Anyways, it stands to reason that if you can go one way, you can go the other by doing the opposite thing. If multiplying by sin(30) eliminated the vector.. well divide by it... or use arcsin.

 

[Entropy]

basically u see stupid and me as a couple of clowns here for ur enjoyment... and ur patience is limited... what's going to happen when it runs out? are u going to close this thread down, too?

Errr... More like ban you guys from the board.

 

[Alkatran]

Errr... More like ban you guys from the board.

A bit off-topic. But yes, you guys are probably going to get banned if you keep up the pace of refusing to believe simple things.

I know this si theory development, but your goal as a physicist should really be to disprove your theory... it's just SO much easier. And if you can't, then you know that your theory is much better for it than if you'd just risked it.

 

[beatrix kiddo]

Errr... More like ban you guys from the board.

But yes, you guys are probably going to get banned if you keep up the pace of refusing to believe simple things.

why would they ban us? i thought chroot told me i could be a mentor...

but your goal as a physicist should really be to disprove your theory...

why would i do that? I'm trying to prove my theory to u guys... i already know there are some flaws in it, but the current model has flaws too. nonetheless, i am going to continue advocating the push theory because i know it's right.

 

[chroot]

but the current model has flaws too.

This is false. There are no known experiments that contradict the standard model, or general relativity, over their domains.

nonetheless, i am going to continue advocating the push theory because i know it's right.

You know it's right? How do you know this?

- Warren

 

[urtalkinstupid]

There is actually a good contradiction between SR and GR.

 

[Alkatran]

why would they ban us? i thought chroot told me i could be a mentor...

Because of these types of comments. (Yes, I got it, I know)

why would i do that? I'm trying to prove my theory to u guys... i already know there are some flaws in it, but the current model has flaws too. nonetheless, i am going to continue advocating the push theory because i know it's right.

By failing to disprove your theory you accumulate evidence towards it's correctness.

I forget who it was that thought that everything he looked at that was a non-black non-raven accumulated evidence that all ravens were black, but I like that logic.

 

[Alkatran]

There is actually a good contradiction between SR and GR.

What a waste of a post. At least tell us what they are instead of looking like you've got nothing more than the words.

 

[chroot]

There is actually a good contradiction between SR and GR.

SR can be derived from GR. Duh.

- Warren

 

[urtalkinstupid]

Ok, you have the elevator experiment that Einstein used for his equivalence principle.

You have one elevator in space and one elevator on earth. Both are being affected by force, but they are different forces. The one on Earth is experiencing force (acceleration) by gravity at a rate of 9.8m/s^2, while the elevator in space is experiencing accelerated forces at a rate of 9.8m/s^2. So, on earth, the acceleration is 1-g. The elevator in space is being accelerated at 1-g equivalence. Therefore, you are unable to tell if you are moving or stationary, right?

Ok, here is how it contradicts with SR. In space, your velocity increase by the appliance of this 1-g force, while on Earth it is unoticeable. So, in space, time will allow you to reach close to the speed of light. What happens as your velocity increases? Yes, your mass increases as well. So, you are able to tell that you are moving by an increase in mass overtime. Your velocity in space will never reach the speed of light, but it will come ever so close, like an asymptote. So, your mass will increase forever as long as you are experiencing this 1-g in space. Thus, you are able to tell if a force is applied by acceleration or gravity by the fact if your mass is increasing or not. Or something like that.

I'm sure you people will find something wrong with this. Just an idea I saw while trying to get information on SR and GR.

 

[chroot]

Thus, you are able to tell if a force is applied by acceleration or gravity by the fact if your mass is increasing or not.

The mass of a body in its own rest frame is always its rest-mass. You can't tell you're moving unless you look out the proverbial window.

- Warren

 

[chroot]

Just an idea I saw while trying to get information on SR and GR.

If you're trying to learn, you should try reading books or reputable journals instead of crackpot websites, I guess.

- Warren

 

[Alkatran]

Ok, you have the elevator experiment that Einstein used for his equivalence principle.


You have one elevator in space and one elevator on earth. Both are being affected by force, but they are different forces. The one on Earth is experiencing force (acceleration) by gravity at a rate of 9.8m/s^2, while the elevator in space is experiencing accelerated forces at a rate of 9.8m/s^2. So, on earth, the acceleration is 1-g. The elevator in space is being accelerated at 1-g equivalence. Therefore, you are unable to tell if you are moving or stationary, right?

Ok, here is how it contradicts with SR. In space, your velocity increase by the appliance of this 1-g force, while on Earth it is unoticeable. So, in space, time will allow you to reach close to the speed of light. What happens as your velocity increases? Yes, your mass increases as well. So, you are able to tell that you are moving by an increase in mass overtime. Your velocity in space will never reach the speed of light, but it will come ever so close, like an asymptote. So, your mass will increase forever as long as you are experiencing this 1-g in space. Thus, you are able to tell if a force is applied by acceleration or gravity by the fact if your mass is increasing or not. Or something like that.

I'm sure you people will find something wrong with this. Just an idea I saw while trying to get information on SR and GR.

I feel it coming... here we go again
You are always a rest with yourself (please don't argue about moving your arms). So ACCORDING TO YOU you always have your rest mass. ACCORDING TO YOU you are exerting a slightly smaller force on Random-Person than what he percieves.

Although this sounds impossible, length contraction and time dilation (and probably a few other factors) cancel this out. So reality doesn't shatter or anything.

 

[urtalkinstupid]

Books and journals are boring... :zzz:

Length contraction and time dilation seem odd! I just told you I ran into this. This guy also goes more indepth into how length contraction and time dilation are factors that contradict with GR.

P.S. When I said "Energy and Work are related," I meant "Energy and Force are related."

 

[Math Is Hard]

When you use the work equation, you multiply by sin(A), which breaks it down to one of the components of the vector. This component is scalar. (You do it all the time when summing vectors)

Just a quick question, Alkatran. What is forming the angle A that you are using to for the sin ratio? I never had any trig come up in solving Work problems so I am not quite visualising this. Whenever I have calculated Work done, I've just multiplied force x distance and then specified the result as a scalar quantity (I had learned somewhere that the product of two vector quantities will always be scalar). The other way I've calculated Work done it is to integrate a force function over a distance. No trig involved here either.
What gives? Just curious.

 

[urtalkinstupid]

This is false. There are no known experiments that contradict the standard model, or general relativity, over their domains.

This is false. The standard model does not provide unity among the four fundamental forces. They contradict each other in a sense they are not able to be combined.

 

[chroot]

This is false. The standard model does not provide unity among the four fundamental forces. They contradict each other in a sense they are not able to be combined.

While it's true that the predictions of GR and QM are incompatible in places such as the insides of black holes, what I said is that are no known experiments contradict either theory, and that is certainly true.

We certainly have more physics left to discover, but there is nothing wrong with the current theories over their respective domains. Any new physics that is discovered will simply be a generalization of these two theories which widens the domain.

- Warren

 

[chroot]

Books and journals are boring... :zzz:

You can choose a lifetime of ignorance if that's what you want. :shrug:

Length contraction and time dilation seem odd!

So does Mandarin Chinese to a native English speaker.

This guy also goes more indepth into how length contraction and time dilation are factors that contradict with GR.

Who is "this guy?" Whoever he is, I suspect that he's listed on crank.net for being, well, a crank. Don't believe everything you read. For someone who claims to be a free thinker, you sure do seem to get caught up in other people's malformed claims pretty often.

- Warren

 

[urtalkinstupid]

So does Mandarin Chinese to a native English speaker.

Not necessarily. My friend is Taiwanese, and when she speaks Mandarin, it does not sound odd.

This "guy" looks like he's pretty intelligent. I don't have the link rigth now, because I'm in the lab at college doing my summer course in mechanical engineering.

I love being ignorant.

 

[chroot]

Not necessarily. My friend is Taiwanese, and when she speaks Mandarin, it does not sound odd.

You understand my point -- that although time dilation and length contraction seem "odd" or counter-intuitive at first, they are not wrong.

This "guy" looks like he's pretty intelligent. I don't have the link rigth now, because I'm in the lab at college doing my summer course in mechanical engineering.

If he says that GR and SR are incompatible, he is quite stupid. I'm sorry, but it's easy to show how SR falls out of GR, and anyone with an even cursory understanding of the theories can show it.

I love being ignorant.

If you eschew books and journals (for whatever reason -- even if they're "boring") and prefer to get your education from crackpots on the internet, you are choosing ignorance.

- Warren

 

[urtalkinstupid]

If you eschew books and journals (for whatever reason -- even if they're "boring") and prefer to get your education from crackpots on the internet, you are choosing ignorance.

At least their babbling is interesting. Books and journals written by scientists are insipid. The same thing everytime you read them. First, they give you a jist of what they are explaining (abstract I guess). Then, they go into experimental evidence. Then, you have observations. Finally, you have a linking between observations and experiments. BORING!

 

[Alkatran]

At least their babbling is interesting. Books and journals written by scientists are insipid. The same thing everytime you read them. First, they give you a jist of what they are explaining (abstract I guess). Then, they go into experimental evidence. Then, you have observations. Finally, you have a linking between observations and experiments. BORING!

You're a science fiction fan, yes? Because from what I just read you PREFER reading about theories that are proposed incorrectly (aka, the ones that are most likely to be wrong).

 

[urtalkinstupid]

You're a science fiction fan, yes? Because from what I just read you PREFER reading about theories that are proposed incorrectly (aka, the ones that are most likely to be wrong).

Stereotypes aren't good. No, I do not like science fiction. The Standard model is not yet proven. Just because it is support experimentally and observationally, does not mean it is what is happening.

CAN WE GET BACK TO WORK? No pun intended...

 

[Alkatran]

Just because it is support experimentally and observationally, does not mean it is what is happening.

That's exactly what it means. (or at least suggests)

As I've said before, experiments are what separate the math from the physics.

 

[urtalkinstupid]

I believe experiments incorporate math in them.

 

[Alkatran]

I believe experiments incorporate math in them.

But math doesn't incorperate experiments in reality.

 

[JoeWade]

please ban already...

enough from ignorant kids who will read and argue the position of every crackpot website they can find while taking NO effort to learn and understand mainstream physics.

 

[Entropy]

I don't have the link rigth now, because I'm in the lab at college doing my summer course in mechanical engineering.

Are we suppost to be impressed that you are taking a course at a college, in a lab? Dude all you just implied to us is that you fool around on the internet instead of doing what you're suppost to do at school, learn.

This is false. The standard model does not provide unity among the four fundamental forces. They contradict each other in a sense they are not able to be combined.

Maybe they aren't really unified in reality? Did you ever think of that as a possiblity? We think they all might be one superforce because electricity and magnetism became unified and then electromagnetism with the weak force. Or maybe it does unite them and we just don't "see" how it does yet.

At least their babbling is interesting. Books and journals written by scientists are insipid. The same thing everytime you read them. First, they give you a jist of what they are explaining (abstract I guess). Then, they go into experimental evidence. Then, you have observations. Finally, you have a linking between observations and experiments. BORING!

Damn! If I didn't know better I'd say they're trying to form and then prove a theory! Whats with these "scientists" and their "scientific method" anyways? Why bother looking at the real world when you can preform arrogent and misinformed thought experiments in your own egocentric universe?[/sarcasm]

Look what you just described is the essence of science. If it bores you then you're in the wrong forum.

 

[urtalkinstupid]

Are we suppost to be impressed that you are taking a course at a college, in a lab? Dude all you just implied to us is that you fool around on the internet instead of doing what you're suppost to do at school, learn.

Hahaha, I get my work done. Though I do internet and work, I'm still able to leave early before everyone else. Unlike them, I know how to work fast. So, implications aren't good.

No, if it bores me, I'm not in the wrong forum. Duh! You people actually explain it in a non-boring way. So, obviously, I'm in the right place.

 

[Entropy]

Hahaha, I get my work done. Though I do internet and work, I'm still able to leave early before everyone else. Unlike them, I know how to work fast. So, implications aren't good.

Why don't you just leave and go on to the internet at home if you're done with all your work?

 

[urtalkinstupid]

Umm...I am home. I left when i posted the post at 7:37 P.M. Which is an hour early, because class ends at 8:35 P.M. CST. So, whatever. This is clearly off the subject.

 

[JoeWade]

he has a point. if i was a physics teacher i would have already stabbed the both of them...

good work avoiding murder by bringing your ignorance here instead of displaying it to people in the real world