本题目来源于试卷: gc physics textbook chapter 6 problems，类别为 IB物理学
[问答题]
Why is it tiring to push hard against a solid wa qd4by7o1 tpi(llrzb c+2c2 s7rp even though you are doing no wp72r+2 zcbs crork?
参考答案: While it is true
that no work is being done on the wall by you, there is work being done inside
your arm muscles. Exerting a force via a
muscle causes small continual motions in your muscles, which is work, and which
causes you to tire. An example of this
is holding a heavy load at arm’s length.
While at first you may hold the load steady, after a time your arm will
begin to shake, which indicates the motion of muscles in your arm.
本题详细解析:
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