题目内容
如图,横截面积为S,下表面与水平面夹角为θ的活塞的质量为M,不计摩擦,若大气压强为P0,则容器中的气体的压强P为( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140610/201406102147304101661.png)
A.P0+
| B.
| ||||||
C.P0+
| D.P0+
|
![](http://thumb.1010pic.com/pic2/upload/papers/20140610/201406102147304101661.png)
以活塞为研究对象,分析受力:重力Mg、外界大气压力P0S,气缸壁的压力N和气缸内气体的压力F,其中F=P?
…①
根据平衡条件得:
P0S+Mg=Fcosθ…②
联立①②得:P=P0+
故选D
![](http://thumb.1010pic.com/pic2/upload/papers/20140610/201406102147304883637.png)
S |
cosθ |
根据平衡条件得:
P0S+Mg=Fcosθ…②
联立①②得:P=P0+
Mg |
S |
故选D
![](http://thumb.1010pic.com/pic2/upload/papers/20140610/201406102147304883637.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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