Concept of Work and Conservative Forces

In summary, work can also be seen as the transformation of energy, as objects can go from having potential energy to kinetic energy. This is possible because work simply converts energy from one form to another. However, in real life, all objects are constantly influenced by external forces, making it impossible for an object to have absolutely zero work done on it. Even in cases where an object seems to have no work done on it, such as in a close to circular orbit, there are still minuscule changes in energy over time.
  • #1
mcnealymt
35
0
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?
 
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  • #2
mcnealymt said:
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.
 
  • #3
Then technically doesn't everything have work being done on it, with the exception of stationary objects.
 
  • #4
mcnealymt said:
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.
 
  • #5
Drakkith said:
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.
 
  • #6
russ_watters said:
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?
 
  • #7
Drakkith said:
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.
 
  • #8
russ_watters said:
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.
 

What is the concept of work?

The concept of work in physics is a measure of the energy transferred when a force is applied to an object and causes it to move a certain distance in the direction of the force.

What are conservative forces?

Conservative forces are those that do not depend on the path taken by an object and only depend on the initial and final positions of the object. Examples include gravity and elastic forces.

How is work calculated for conservative forces?

Work done by conservative forces can be calculated using the equation W = -ΔU, where W is the work done, ΔU is the change in potential energy, and the negative sign indicates that the work is done against the force.

What is the significance of conservative forces in physics?

Conservative forces play a critical role in the conservation of energy. The total mechanical energy of an object in a conservative force field remains constant, as energy is transferred between kinetic and potential energy.

Can non-conservative forces do work?

Yes, non-conservative forces, such as friction and air resistance, can do work. Unlike conservative forces, the work done by non-conservative forces depends on the path taken by an object and results in a loss of mechanical energy.

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