作者pugboy (缘投肥)
看板Grad-ProbAsk
标题[理工] [物理]-请问一些定律问题
时间Wed Oct 14 12:13:40 2009
不好意思 我想问各位物理高手两题分别为
（a）on mars,the acceleration due to gravity is 3.71 m/s2. What could a rock's
velocity be 3s after you dropped it on mars？
how far would a rock fall in 3 s if you dropped it on mars?
问题（a）的解答我只想得出3.71 * 3 =11.13m
1/2*3.71*3^3＝51.08m
之後就不之如何求解...
（b）the builders of the pyramids used a long ramp to lift
20000-kg(22-ton)blocks.if a block rose 1 m in height while traveling 20 m
along the ramp's surface, how much uphill force was needed to push it up the
ramp at constant velocity
how much work was done in raising one of the blocks in problem 15 a height of
50 m
问题（b）我只想到m*g*sin系塔＝F
意思是20M*9.8*sin系塔 ＝答案吗？
sin系塔又如何求出...？
b的第二问题是把20m改成50m就ok吗？
麻烦一下 感恩！
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※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 122.117.10.111
1F：推 fairwarning:格式要加 - 喔 10/14 12:24
2F：→ fairwarning:在[物理]面要加 - 10/14 12:24
3F：→ fairwarning:物理的格式是[] ^^ 10/14 12:24
※ 编辑: pugboy 来自: 122.117.21.138 (10/14 12:48)
4F：推 youmehim:(a)H=0.5gt^2 (b) F=mgsinθ sinθ=1/20 W=mgh 10/14 14:12
5F：→ pugboy:不好意思再问一下 （a）小题中的第二个问题是求how far 可 10/14 21:57
6F：→ pugboy:是H＝0.5*g*t^2 那how far 是 m*t吗 那m是如何求？ 10/14 22:01
7F：→ pugboy:还有(b)小题中W＝mgh 里得h＝0.5*g*t^2 中的t如何求出？ 10/14 22:03
8F：→ pugboy:感恩..！ 10/14 22:05
9F：推 youmehim:(a) 哪来的m.. (b) h = 50m 10/14 22:48
10F：→ pugboy:我是想请问（a）小题的第二小题不是求how far吗 可是H不是 10/15 22:43
11F：→ pugboy:高度吗？这样要如何求出how far？ 10/15 22:44
12F：→ pugboy:还有（b）小题的第二小题H=50M 那w=mgh中的m要如何求出.. 10/15 22:45
13F：→ pugboy:不好意思 小弟是物理白痴 不懂太多 麻烦可以帮我解惑 感恩 10/15 22:46