Force... What is energy's role?

*Momento*

Quote by Drakkith

The interaction by which any transfer of energy takes place is the result of a force. Without a force there would be no interaction between two particles and no energy would be exchanged.

Thank you! Thats what I've been looking for. Force is crucial in a system to convert energy from its orignal form to another. Thats why we mainly use the formula W = F x D...

I just need to know that force is the tool for energy to use to be able to do "work". Without it you would not be able to do anything with that energy. Hope I'm on the right page here.

*Momento*

Quote by Dead Boss

I would say force is a result of interaction not the other way around.

Honestly doubt that.

CWatters

Quote by Momento

I just need to know that force is the tool for energy to use to be able to do "work". Without it you would not be able to do anything with that energy. Hope I'm on the right page here.

I think that even applies to electrical or chemical systems.

*Momento*

Quote by CWatters

I think that even applies to electrical or chemical systems.

I think it would apply to all those system. However, heat is another different matter...

sophiecentaur

Quote by haruspex

It's not so much a matter of expanding the meaning. It's more that the meaning of the word "work" has tended to contract to cover only mechanical work in most usage. It's a bit like the use of "forensic" to mean specifically forensic science. It really means "pertaining to law".
Early statements of the laws of thermodynamics included "heat is work and work is heat". The term energy was not so widespread.
But I was wrong to say thermodynamic work meant heat - it's everything except heat. For the rest, see http://en.wikipedia.org/wiki/Work_%28thermodynamics%29.

Flanders and Swann did a memorable rendition of this, way back.

Drakkith

Quote by Momento

Thank you! Thats what I've been looking for. Force is crucial in a system to convert energy from its orignal form to another. Thats why we mainly use the formula W = F x D...

I just need to know that force is the tool for energy to use to be able to do "work". Without it you would not be able to do anything with that energy. Hope I'm on the right page here.

Well, I would say that energy doesn't do work at all. Forces do work and a change is incurred in the system. Energy is simply a measure of how much work something can do.

Nano-Passion

Quote by Drakkith

Well, I would say that energy doesn't do work at all. Forces do work and a change is incurred in the system. Energy is simply a measure of how much work something can do.

I think it is a pointless distinction. Let us forget about force fields so we can separate force and energy from each other. Now if I throw a ball in space, we have something called kinetic energy and that energy can do work on object B when it is in contact.

But you could just as easily say that it is the force that did work by the equation F=ma. I accelerated mass A and it hits object B with force F and does work.

So which one is the "culprit"?

Drakkith

The work done is going to depend on all the properties of an object, from it's mass to it's velocity to whichever forces it interacts by. (Along with the same things for the object it interacts with)

But if one were to choose which one does the work I would say it is the force. If two particles don't interact by a force at all, then they cannot perform work on each other. But then would the particles still have energy, at least with respect to one another? I don't know.

*Momento*

Quote by Drakkith

The work done is going to depend on all the properties of an object, from it's mass to it's velocity to whichever forces it interacts by. (Along with the same things for the object it interacts with)

But if one were to choose which one does the work I would say it is the force. If two particles don't interact by a force at all, then they cannot perform work on each other. But then would the particles still have energy, at least with respect to one another? I don't know.

I really like you descriptions! I believe that FORCE is the key for work without as I said before work can't be done. Really really interesting thing. Thank you so much for you're answers!

For all the others I appreciate you're effort too! Thing is we could all agree at a certain point that without force the system can NOT do any work at all! I'd be glade to read more ideas from anyone else!

*Momento*

If force was applied to an object will there be work done? Would there be energy stored?

I think that force is the main reason why energy could possibly be converted... Like friction its a force on moving objects it converts their energy into heat, its possible that it could convert it to another form of energy?

Nano-Passion

Quote by Drakkith

The work done is going to depend on all the properties of an object, from it's mass to it's velocity to whichever forces it interacts by. (Along with the same things for the object it interacts with)

But if one were to choose which one does the work I would say it is the force. If two particles don't interact by a force at all, then they cannot perform work on each other. But then would the particles still have energy, at least with respect to one another? I don't know.

True, for kinetic energy to happen there needs to be a force (acceleration or "imbalance" if you will).

Nano-Passion

Quote by Momento

If force was applied to an object will there be work done?

Yes work is done when ever you displace an object X distance. Force does work because it accelerates things, and hence displaces it.

Would there be energy stored?

Well it kind of depends on what you mean by stored. Under certain parameters like in gravitational fields where energy is conservative, potential energy is stored.

Based on other principles, you can argue that kinetic energy is given to the object since it picks up velocity. Whether you want to call that stored is semantics.

I think that force is the main reason why energy could possibly be converted... Like friction its a force on moving objects it converts their energy into heat, its possible that it could convert it to another form of energy?

I'm not following this point.

*Momento*

Quote by Nano-Passion

I'm not following this point.

Look at the rotational kinetic energy of a wheel that is being rotated by a motor for example.
That motor would convert electricity into mechanical energy to rotate the wheel. Lets say based on the work model 1000J was supplied of electricity, if the motor would lose some of that energy due to countless reason. One of them is "Friction" of the bearings.

Now friction is a force, it distribute a small amount of the 1000J to another form of energy like heat,sound,etc...

grantwilliams

Quote by Momento

If force was applied to an object will there be work done?

Isn't that only true if force is in the same direction as motion?

Drakkith

Quote by grantwilliams

Isn't that only true if force is in the same direction as motion?

No, if you apply a force against an object to slow it down you have done work.

grantwilliams

Quote by Drakkith

No, if you apply a force against an object to slow it down you have done work.

And I guess a torque applied causes work to be done if the object has a radial displacement.. my bad.

*Momento*

Quote by Drakkith

No, if you apply a force against an object to slow it down you have done work.

Makes sense. A force was applied over a distance to stop a moving object which represents this model: W = F x D?

Thats way work is done?

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Momento	If force was applied to an object will there be work done? Would there be energy stored? I think that force is the main reason why energy could possibly be converted... Like friction its a force on moving objects it converts their energy into heat, its possible that it could convert it to another form of energy?