1 . 把物体放在冷空气中冷却,如果物体原来的温度是
(
),空气的温度是
(
),经过t分钟后物体的温度T(
)可由公式
求得.把温度是
的物体,放在
的空气中冷却t分钟后,物体的温度是
,那么t的值约等于(参考数据:
,
)( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e9a724b59c890095baa5cb73e267c44.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa088a4729226b696c536845791d4c02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/635ccd929471d564cc9d2d96266b34d1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa088a4729226b696c536845791d4c02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa088a4729226b696c536845791d4c02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f87667112b9566e524d5ae9923b49caf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a85957e50b2f170a2539c2f001e244f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93c534228d6a812977052bc1afa5a95f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dce3bddc9396deaf856eca6ac14594b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7c0309456de2cd6420ece4fbc5eeddb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9405361d7be3c9e4d462a4e955d8fe3c.png)
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2 . 物体在常温下的温度变化可以用牛顿冷却定律来描述:设物体的初始温度是
,经过一段时间t后的温度是T,则
,其中
称为环境温度,h称为半衰期,现有一杯用88℃热水冲的速溶咖啡,放在24℃的房间中,如果咖啡降到40℃需要20分钟,那么咖啡从40℃降温到32℃时,还需要( )分钟.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/635ccd929471d564cc9d2d96266b34d1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4cfd43010acffa2d7180548911fd109.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/212baa7c3eed6574b6edae95538a7765.png)
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