# Energy spent on holding a kg

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

cepheid
Staff Emeritus
Gold Member
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.

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?

cjl