How Much Energy is Spent Holding 1kg for an Hour?

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SUMMARY

Holding 1 kilogram at a height of one meter for an hour does not involve mechanical work, as the displacement of the object is zero. However, the human body expends energy due to the inefficiency of muscle contractions required to maintain the position. Factors such as muscle tone, circulation, and metabolism significantly influence the energy expenditure, rather than just the weight and gravity. In contrast, inanimate objects like a table do not expend energy to hold weight, while machines like helicopters do require energy to counteract gravitational forces.

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jc.int
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hello,
If I hold 1kilogram at one meter of the groud during an hour, what would be the theoretical energy I am spending (in joules for example)?

Thank you,
Jaimie
 
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You're not doing any work because the displacement of the object is 0.

However, your muscles, as a biological system, are inefficient. To just bear a load without moving it, they must alternately contract and relax rapidly. As a result, your body expends chemical energy and you do end up feeling tired.
 
cepheid said:
You're not doing any work because the displacement of the object is 0.

However, your muscles, as a biological system, are inefficient. To just bear a load without moving it, they must alternately contract and relax rapidly. As a result, your body expends chemical energy and you do end up feeling tired.

Indeed. And as a result, the amount of energy expended depends more on your muscle tone, circulation, metabolism, etc. then on simple physics of the weight and gravity. Place the same kilogram on a solid table for an hour and it becomes obvious that no energy is being expended (the table does not run down its batteries/use up its fuel, etc.)
 
I agree with you but when a helicopter holds a weight it is using energy to compense the gravity force, isn't it?
 
Yes, because once again, it is inefficient. A helium balloon can hold a weight as well, and it would require no energy input to do so.
 

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