题目:
质量为25㎏的小孩坐在秋千上,小孩离拴绳子的栋梁2.5m.如果秋千摆到最高点时,绳子与竖直方向的夹角是60°,当秋千板摆到最低点时(不计空气阻力,g取10m/s2),求:
(1)小孩的速度为多大?
(2)秋千板对小孩的压力是多大?
答案:
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