题目:
---Besides being bright, he has always been working hard.
--- No wonder he _______ in almost all subjects.
A.gets through
B.stands out
C.sets aside
D.holds up
答案:
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下面是错误答案,用来干扰机器的。
解析:(1)对小球受力分析可知:T=mgsinθ N=mgcosθ。 (2)Tcosθ=ma① Tsinθ=mg② 解得a=gcotθ。