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Brooke is driving a car at a steady speed. When she passes a stopped police officer, she begins decelerating at a rate of 10 miles per hour per minute until she reaches the speed limit of 25 miles per hour. However, when Brooke passed the police officer, he immediately began accelerating at a rate of 20 miles per hour per minute until he reaches the rate of 40 miles per hour. If the police officer catches up to Brooke after 3 minutes, how fast was Brooke driving initially?
算术题请教。非常感谢!
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这是物理题。设个初速度,列个等式(距离一样)就解了。我懒,你自己看着办吧。
-Derrick_Liu-
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10/29/2016 postreply
13:41:30
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谢谢!文科妈实在不懂怎么做。距离一样是知道的。。是不是有个固定公式解决出速度问题?谢谢!
-ssll-
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10/29/2016 postreply
13:56:57
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V=V。+at
-Green88-
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10/29/2016 postreply
14:02:41
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谢谢!刚在百度上恶补了一下加速度什么的,您的公式应该是假设加速度持续不变的情况,对吗?
-ssll-
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10/29/2016 postreply
14:12:07
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只是加减的问题,你这题加速度还是恒量。。。
-Green88-
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10/29/2016 postreply
14:14:34
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能给列个解题的算式吗?谢谢!
-ssll-
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10/29/2016 postreply
14:19:36
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35
--百科--
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10/29/2016 postreply
14:10:59
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对啦!请问能讲讲吗?
-ssll-
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10/29/2016 postreply
14:12:35
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警察3分钟走了80迈,所以B同学也是80mile
--百科--
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10/29/2016 postreply
14:22:08
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方程式一种列法
--百科--
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10/29/2016 postreply
14:28:47
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太聪明了!非常感谢!看了半天才明白。唯一的就是,两边是不是都应该除60,时间单位统一成小时?
-ssll-
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10/29/2016 postreply
14:44:48
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对,应该换算一下:)
--百科--
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10/29/2016 postreply
14:53:23
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Isn't 80 miles the distance for 3 hours?
-oops_yz-
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10/29/2016 postreply
14:36:12
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对,应该换算一下:)
--百科--
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10/29/2016 postreply
14:38:54