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-   -   work done holding a weight? (http://www.physicsforums.com/showthread.php?t=123063)

mahannan Jun6-06 02:09 PM

if a man is lifting weight while standing at rest, is he doing work microscopically?

Doc Al Jun6-06 02:13 PM

Quote:

Quote by mahannan
if a man is lifting weight while standing at rest, is he doing work microscopically?

If he's lifting it microscopically. :smile:

Do you mean holding a weight without moving it? Or lifting a weight while standing in one place?

Hootenanny Jun6-06 02:19 PM

I think we have been through this discussion before, the physics definition of work is fundementally different to the physiological defintion of work. I'll try and dig out a link to the other thread.

mahannan Jun6-06 02:37 PM

Quote:

Quote by Doc Al
If he's lifting it microscopically. :smile:

Do you mean holding a weight without moving it? Or lifting a weight while standing in one place?

I mean, do his muscles perform any work as he is standing while lifting the weight at rest?

Doc Al Jun6-06 02:43 PM

I will assume you mean that the man is holding a weight without moving it. In that case while there is no mechanical work done on the weight, there is certainly work going on in your muscles (they continually tense and relax)--that's why you get tired just holding a weight, even though you are not moving it. That internal work requires energy.

Doc Al Jun6-06 02:53 PM

We beat this one to death here: http://www.physicsforums.com/showthread.php?t=119026

Hootenanny Jun6-06 02:55 PM

Quote:

Quote by Doc Al

You beat me to it Doc :rolleyes: Was your search function running slow? Mine took ages to display...

Doc Al Jun6-06 03:02 PM

Quote:

Quote by Hootenanny
Was your search function running slow? Mine took ages to display...

Yes, way too slow to be useful. But the thread wasn't that old, so I found it in the list.


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