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math t calculus
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a ladder 5 m long leans against a vertical wall.the bottom of the ladder is pulled along the ground away from the wall at a constant rate of 0.3ms^-1.How fast will the top of the ladder be falling at the instant when its bottom is 2m away from the wall?
answer:0.13ms^-1 |
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发表于 18-1-2010 05:58 PM
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a ladder 5 m long leans against a vertical wall.the bottom of the ladder is pulled along the ground ...
數學神童 发表于 18-1-2010 04:10 PM 
sorry,答案应该-0.13m /s
因为跌下去的话，vertical height decreases .. |
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