Mechanical work of muscles: How much work do you actually do?

[Angstromicus]

One of the reasons why jaw muscles are so strong is that the jaw is a relatively short lever for muscles to pivot. But, for example, the biceps have a much longer lever to work with, so they have to do more work to lift the same amount of weight.

For, say, an arm that's about 1/2 of a meter long (about 1.5 feet), and the person curled a ten kilogram weight. How much weight would the bicep actually be pulling - a hundred kilograms perhaps? More? Less?

[anomaly]

Wouldn't measurement of actual weight be dependent on what position the arm is in at a particular moment while lifting?  Wouldn't work, or how much energy it takes to lift the weight be a better measurement of the strength of the muscle?

If I could just remember angular mechanics from last year, I could do this.
Where are my notes...

[Zero Angel]

I'd say that the main reason why the jaw muscles are so strong is because they get worked out so often, by talking and chewing. Anyways I'd say that if the weight is the same (including the arm) then i'd say it would be equivalent.

Lets say that a person had 2 stats:

Strength -- Max lifting strength
Endurance -- How many repetitions can be done at max lifting strength before the arm gives out.

If we defined the pivot as "point A" and the object at the end of the arm as "point B":

A longer 'arm' would be harder on the endurance, because "point B" of the arm must be moved a greater distance. It would be as if you were standing on a balcony and there was a can of paint attached to a string and you had to pull it up -- a longer arm would be the equivalent of 6 meters instead of 2.

IOW, it would be like drawing an arc with a metal compass, and measuring the length of the arc in relation to the size of the arc.

[Zero Angel]

Using the formula (x*3.14)/2 = y also phrased as x*1.57 = y

where x is the length of the arm and y is the length of the arc

We can derive that an arm that is 3m long, must move an object 4.71 meters
Whereas an arm which is 10m long must move the arm 15.7m

Now, the calculations on how much 'work' this entails would NOT be exactly 1.57, because we have to take into account the fact that less force is needed the further up the arc you go.

That's just my best guess until we can get someone in here who has REAL physics knowledge.

[OvermindDL1]

We did this in physics years ago, I can probably remember it if you really want to know, but I kind of dumped most of that non-generic stuff out over the past 5 years...
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