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我们现在使用的图钉的头部是圆形的,如果不小心掉在地上,图钉尖的那头通常会朝上,走路的人一不留神踩到它就会戳伤脚。为什么图钉的尖头容易朝上呢?经过研究我发现,图
The pins that we are using now are round in shape. If you accidentally fall to the ground, the tip of the pushpin will usually be facing upwards. If you walk on it, you will pound your foot as soon as you step on it. Why is the pushpin pointed easily up? After research I found that figure