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In: Physics

A girl of mass, m = 40 kg has osteoporosis which weakens her bones. From a...

A girl of mass, m = 40 kg has osteoporosis which weakens her bones. From a kneeling position, she topples forward onto her elbows with her upper arms extended vertically downwards on impact with the ground. In falling forward, her centre of mass lowers by a height, h = 50 cm and she absorbs all of her kinetic energy from her fall into her two humerus bones (one bone in each upper arm).

Determine an equation for the stress in each humerus bone, ?, in terms of m, h, the acceleration due to gravity, g, Young’s modulus for bone, Y, the cross sectional area of each humerus bone, A and the length of each humerus bone, l. State any laws used. Now, determine the minimum rupture strength required for the girl’s humerus bones such that she doesn’t break them, given in units of N/m2 . Take l = 20 cm, A = 3.0 cm2 and Y = 1.4 x10^10 N/m2 .

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genius_generous answered 6 months ago
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