Potential energy

[Wizard of Whatever]

Your original question was pretty basic.

But with a different emphasis than one learns in school.

 

[exchemist]

Your original question was pretty basic.

There is more than one meaning for a BS in physics.

 

[Wizard of Whatever]

There is more than one meaning for a BS in physics.

The world will never learn, as long as they think they already know. This applies to any knowledge.

 

[Pinball1970]

world will never learn, as long as they think they already know. This applies to any knowledge

We do not think we already know, we trust the physics we have been taught because we use it and it works.
I cannot speak for exchemist but I think he like me will be interested to see how Dark Energy pans out. This is a new type of energy, unknown origin and properties.
New unexpected and unexplained phenomena being investigated by scientists using the scientific method.

 

[Pinball1970]

But with a different emphasis than one learns in school.

I don't know what that means.

 

[exchemist]

The world will never learn, as long as they think they already know. This applies to any knowledge.

I’m willing to explore a new theory of yours, if you can articulate it, in Alternative Theories.

But I have to say your opening post was not written by someone with a good, clear understanding of physics.

 

[exchemist]

We do not think we already know, we trust the physics we have been taught because we use it and it works.
I cannot speak for exchemist but I think he like me will be interested to see how Dark Energy pans out. This is a new type of energy, unknown origin and properties.
New unexpected and unexplained phenomena being investigated by scientists using the scientific method.

I’m more interested in progress in the study of abiogenesis, actually. Dark Energy seems to be all mixed up with zero point energy of the vacuum and I quickly get lost there, as I never studied QFT.

 

[Wizard of Whatever]

I’m willing to explore a new theory of yours, if you can articulate it, in Alternative Theories.

But I have to say your opening post was not written by someone with a good, clear understanding of physics.

My understanding of physics is very clear, just not a regurgitation of a physics textbook.

 

[exchemist]

My understanding of physics is very clear, just not a regurgitation of a physics textbook.

I just don’t believe it is, to judge by your comments on this thread. But OK then, to give you the benefit of the doubt, let’s have your explanation of this alternative way you propose for treating energy. As I understand it so far, it is something to do with associating forces with “hidden” energy, which can become manifest in certain circumstances. Can you elaborate?

 

[Wizard of Whatever]

I just don’t believe it is, to judge by your comments on this thread. But OK then, to give you the benefit of the doubt, let’s have your explanation of this alternative way you propose for treating energy. As I understand it so far, it is something to do with associating forces with “hidden” energy, which can become manifest in certain circumstances. Can you elaborate?

Potential energy is not real to me. The weight in a gravitational field has no real energy that is called potential energy. To gain kinetic energy from the gravitational force a real energy must be transferred. If this is not the case, you are creating kinetic energy from nothing..You will say this comes from the position in the G field. However, this position contains no real energy. From a conservation of energy perspective, I see no problem with me idea.

 

[exchemist]

Potential energy is not real to me. The weight in a gravitational field has no real energy that is called potential energy. To gain kinetic energy from the gravitational force a real energy must be transferred. If this is not the case, you are creating kinetic energy from nothing..You will say this comes from the position in the G field. However, this position contains no real energy. From a conservation of energy perspective, I see no problem with me idea.

What do you think happens to the energy expended by a crane lifting a massive object?

 

[Wizard of Whatever]

What do you think happens to the energy expended by a crane lifting a massive object?

The crane lifts the weight giving it a kinetic energy. The force used by the crane transfers energy to the weight acting against the gravitational force trying to pull the weight back down. The cranes force and energy come from what fuels it.

 

[exchemist]

The crane lifts the weight giving it a kinetic energy. The force used by the crane transfers energy to the weight acting against the gravitational force trying to pull the weight back down. The cranes force and energy come from what fuels it.

I'm unsure what you mean by the crane transferring energy to the weight acting against gravitational force. When the weight reaches the intended height, and the crane stops lifting, i.e. the weight no longer has kinetic energy, are you saying the weight has more energy than it did when it was on the ground, or the same amount?

 

[Wizard of Whatever]

I'm unsure what you mean by the crane transferring energy to the weight acting against gravitational force. When the weight reaches the intended height, and the crane stops lifting, i.e. the weight no longer has kinetic energy, are you saying the weight has more energy than it did when it was on the ground, or the same amount?

In terms of what I consider real energy, the same.

 

[exchemist]

In terms of what I consider real energy, the same.

OK so where has the energy expended by the crane gone?

 

[billvon]

If a force increases the kinetic energy of a mass, where does that energy come from if energy cannot be created or destroyed.

From the force that does work on the mass.

In the crane weight example, no real energy is transferred, only the potential of the weight to gain kinetic energy from falling. The gain in kinetic energy is created by the gravitational force. Where does that force get the energy to transfer?

The change in potential energy is provided by the electricity that runs the crane. The energy in the weight comes when it is released, and can do work while it is descending.

 

[billvon]

The crane lifts the weight giving it a kinetic energy.

No. If you lift it very slowly it takes very little POWER and adds almost zero KINETIC energy since it is moving slowly. However, over time it will transfer a lot of ENERGY in the form of potential energy. This is actually used in a power storage scheme where cranes lift large blocks of concrete when there is lots of electrical energy available, then lowers them (and uses its motor as a generator to recover the energy) when energy is needed by the grid.

The force used by the crane transfers energy to the weight acting against the gravitational force trying to pull the weight back down.

Right. Potential energy.

The cranes force and energy come from what fuels it.

Not quite. You can have a huge force that does not require any energy. For a simple example, a parked A380 is imposing a huge force on the ground underneath its wheels. But without motion, force does not give you energy (or work.)

 

[Wizard of Whatever]

OK so where has the energy expended by the crane gone?

It was used to create and destuff the kinetic energy of the weight.

 

[Wizard of Whatever]

From the force that does work on the mass.

That's what I've been saying. The force transfers eb ergo ro the weight.

The change in potential energy is provided by the electricity that runs the crane. The energy in the weight comes when it is released, and can do work while it is descending.

It only descends because energy is transferred from the G force.

 

[Wizard of Whatever]

It was used to create and destuff the kinetic energy of the weight.

I'll end the discussion here. You will never convince me that potential energy is real and I will never convince you that force transfers its own internal energy. Have a nice day.