If you jump from a desk and land stiff-legged on a concrete floor,(adsbygoogle = window.adsbygoogle || []).push({});

the chance is good that you will break a leg. To see how this

happens, consider the average force stopping your body when you

drop from rest from a height of 1.00 m and stop in a much shorter

distance d. Your leg is likely to break where the cross-sectional area

of the bone (the tibia) is smallest. This is at a point just above the

ankle, where the cross-sectional area of the bone is about 1.60 cm^2.

A bone fractures when the compressive stress on it exceeds about

1.60*10^8 N/m^2. If you land on both legs, the maximum force your

ankles can safely exert on the rest of your body is then about……..

2 (1.60*10^8 N/m^2) (1.60*10^-4 m^2) = 5.12*10^4 N.

Calculate the minimum stopping distance d that does not result

in a broken leg if your mass is 60.0 kg. Don’t try it! Bend your knees!

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# Homework Help: Urgent Cant Figure This Out

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