(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Why are mammals as large as they are and not much larger?

2. Relevant equations

Two figures are given. One of the mammal with size S and mass M. Femur is the thigh bone of the mammal with l being the length of the femur, d being the thickness of the femur and A being the cross sectional area:

i)l ∞ s - length of the femur is proportional to the size

ii) m∞s^{3}∞l^{3}

iii) pressure ∞ weight/Area ∞ m/d^{2}

iv) m ∞d^{2}

v) d^{2}∞l^{3}

Therefore, d ∞ l^{3/2}

3. The attempt at a solution

These have been worked out, but I am confused at how length is proportional to the size. Is volume the size? In fact, I don't understand the whole thing. Please help. I have looked at the MIT video three times and still confused. Sorry for being so dumb but I don't hesitate to ask.

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# Homework Help: Measurements - relation between mass and size

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