推 o189830:看到題目不禁要慶幸自己沒修普物...同志!!加油吧!!(拍肩) 11/15 21:50
→ ansansansans:害我很高興，想說終於有人回應我了，結果是... 11/15 22:25
if you jump from a desktop and land stiff-legged on a concrete floor,
you run a significant risk that you will break a leg. to see how that
happens,consider the average force stopping your body when you drop from
rest from a height of 1m and stop in a much shorter distance d.
your leg is likely to break at the point where the cross-sectional area
of the bone is smallest. this point is just above about 1.6平方公方.
a bone will fracture when the compressive stress on it exceeds about
160000000 N/平方公尺.
if you land on both legs, the max force that your ankles can safely exert
on the rest of your body is then about
2x160000000x0.00016=51200 (N)
calculate the min stopping distance d that will not result in a broken leg
if your mass is 60kg.
我打了那麼久，同情一下我嘛
題目句子很簡單
但是我每看完一次就腦袋空白了
所以，先大致跟我說題目在說什麼，可以嗎??!!
當然還是要解題哈哈
答案是1.16cm
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