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GrandMasterK

Does force of holding something generate constant energy?

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I was staring at the hook in the wall that holds up my guitar and I noticed over time it has gradually started pealing at the top. It occurs to me that the weight of the guitar is very gradually pulling the hook out of the wall and may very well collapse years from now. So it got me wondering.......when you hold something up, force is being applied constantly. Does that mean energy is being used constantly to hold the guitar up? Or am I thinking about it wrong?

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If there is no motion, there is no energy involved because the work done is zero. It's completely static. That's the idealized version.

 

However, in real-world situations, there is motion — there's vibration going on, both microscopic and macroscopic. So you are doing work on that scale, and breaking bonds between atoms and breaking down whatever structure is in the material. You will eventually reach the point where the wall/hook can't exert the force it needs to.

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It is constantly exerting a force though yes? Does that require energy? Can you harness energy from a situation like that?

 

It requires motion for work to be done. That's the only way to harvest mechanical energy.

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One way to look at it is that the hook/guitar system has potential.

Over time all the factors Swansont has mentioned degrade the stickiness of the hook.

When it finally lets go, the potential is turned into motion as the guitar and hook fall to the ground under the influence of gravity.

We can, then, harvest this kinetic energy, and use it to do work.

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I was staring at the hook in the wall that holds up my guitar and I noticed over time it has gradually started pealing at the top. It occurs to me that the weight of the guitar is very gradually pulling the hook out of the wall and may very well collapse years from now. So it got me wondering.......when you hold something up, force is being applied constantly. Does that mean energy is being used constantly to hold the guitar up? Or am I thinking about it wrong?

 

 

 

It requires motion for work to be done. That's the only way to harvest mechanical energy.

 

Work has a very specific meaning with regards to energy - but the question was not whether the hook is doing work to stay up - but rather is the hook expending energy to stay up?

 

What is the proof that the hook is NOT expending energy in order to stay put?

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Work has a very specific meaning with regards to energy - but the question was not whether the hook is doing work to stay up - but rather is the hook expending energy to stay up?

 

What is the proof that the hook is NOT expending energy in order to stay put?

"Expending energy" and "work" are synonymous for mechanical systems. There is no other path.

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I'm still kinda confused. The hook is using energy to keep the guitar from falling isn't it? Or at least the wall or glue that's keeping the hook from falling? If it were a person, we'd be using energy to hold it up or our arm would fall no? Doesn't the same go for an object preventing another object from moving? Like if I were pushing on somebody to keep them from moving forward or even just a wall that I'm leaning on? Why is there no way to harness this in any fashion?

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I'm still kinda confused. The hook is using energy to keep the guitar from falling isn't it? Or at least the wall or glue that's keeping the hook from falling? If it were a person, we'd be using energy to hold it up or our arm would fall no? Doesn't the same go for an object preventing another object from moving? Like if I were pushing on somebody to keep them from moving forward or even just a wall that I'm leaning on? Why is there no way to harness this in any fashion?

 

It takes energy to hold something up because parts of your arm are in motion continually. But you aren't doing work if the object isn't moving. There's no energy you can extract from it.

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What is the proof that the hook is NOT expending energy in order to stay put?

Hooks don't need batteries.

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Can generate heat from deformation. Something like a heavily loaded wire coat hanger is probably easier to consider.

 

It can't provide any more power though than if you simply dropped it. Same amount of potential energy converted over a longer span of time.

 

On a more practical note you might want to consider reinstalling. Sounds like it wasn't in a stud. Fun to explore your own walls, especially if you make your own stud finder out of a couple permanent magnets and a couple of plastic bottle caps. :)

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They're only $20 at the hardware store !

What' re you Scottish ?

 

( I'm only kidding, Ophiolite )

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