Concept of Work and Conservative Forces

[mcnealymt]

Can work also be the transformation of energy? For instance, an object in free fall goes from an initial height (that has potential energy) to a final height where there is kinetic energy. If energy is conserved then how is work being done?

 

[russ_watters]

Can work also be the transformation of energy? For instance, an object in free fall goes from an initial height (that has potential energy) to a final height where there is kinetic energy.

Yes.

If energy is conserved then how is work being done?

Because all the work does is convert the energy from one form to another.

 

[mcnealymt]

Then technically doesn't everything have work being done on it, with the exception of stationary objects.

 

[Drakkith]

Then technically doesn't everything have work being done on it, with the exception of stationary objects.

No, an object moving relative to another object, but with no force being applied to it, is not having any work done on it.

That said, this is not possible in real life. All objects have constantly changing forces exerted on them.

 

[russ_watters]

No, an object moving relative to another object, but with no force being applied to it, is not having any work done on it.

That said, this is not possible in real life. All objects have constantly changing forces exerted on them.

Never exactly zero, but darn close to it. An object in a close to circular orbit can stay that way for billions of years with little change in energy.

 

[Drakkith]

Never exactly zero, but darn close to it. An object in a close to circular orbit can stay that way for billions of years with little change in energy.

Only in relation to the object it is orbiting around. In real life planets orbit stars, which orbit galaxies, which move in the cosmos. And then you have things like the bazillions of small objects floating through space, all of them influencing us while we do the same to them. Does that sound right?

 

[russ_watters]

Only in relation to the object it is orbiting around. In real life planets orbit stars, which orbit galaxies, which move in the cosmos. And then you have things like the bazillions of small objects floating through space, all of them influencing us while we do the same to them. Does that sound right?

Sure, but the change in energy in any of those interactions is vanishingly small over vast periods of time. I wasn't trying to say you were wrong, just that in some cases, the level of precision needed to see an energy loss is really high.

 

[Drakkith]

Sure, but the change in energy in any of those interactions is vanishingly small over vast periods of time. I wasn't trying to say you were wrong, just that in some cases, the level of precision needed to see an energy loss is really high.

Ah, ok. I see what you're getting at now.