本题目来源于试卷: gc textbook chapter 8 Rotational Motion，类别为 unclassified
[问答题]
Why is it more difficult1x 7dl9bp19fr qnvtx 9 to i*/nyn/ l0rq z(ld-cl do a sit-up with your hands behind your head than when your ard( *ll/cnq/l 0in-z ryms are stretched out in front of you? A diagram may help you to answer this.
参考答案: When you do a sit-up, torque from
your abdomen muscles must rotate the upper half of the body from a laying-down
position to a sitting-up position. The
larger the moment of inertia of the upper half of the body, the more torque is
needed, and thus the harder the sit-up is to do. With the hands behind the head, the moment of
inertia of the upper half of the body is larger than with the hands
outstretched in front.
本题详细解析:
暂无
| 
Post time 2025-2-18 20:00:22