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Here I'm thinking of a man trying to push a wall.

I have 2 understandings of work in physics.

1: W=Fd

Here if you are pushing a wall, no work is being done.

2: The conversion of energy from one form to another.

If an electric heater produces 1000 J per sec, then 1000 J of electric energy are being converted into 1000 J of heat energy per sec. I alway thought of this as 1000 J of work being done. Yet there is no motion.

Am I wrong about the 2nd definition?

When a man tries to push a wall chemical energy from his body is being converted to heat energy in his muscles and maybe some heat energy in the wall. Energy is being converted yet no motion occurs.

Then I remembered that heat itself is motion of particles, so heat is motion. If heat is being generated without macroscopic motion can we say that work is being done?

Which definition is true and if not true then why not?

Kantura
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1 Answers1

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No mechanical work is done, you could do the same "work" with some wood or iron bar pushing for very long time. So as human it is considered work, but so is laying in bed, you need energy to live.

trula
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