查人人中国名人网老款东风多利卡:``一道高一物理, 请指教 !!!
来源：百度文库 编辑：查人人中国名人网 时间：2024/05/05 02:39:14
圆圈为定滑轮
Q,P是砝码,质量都为M
B是小砝码,质量为m
用该装置测定重力加速度g,测出时间t内砝码P通过的距离,利用M,m,t,s写出g的表达式.
答案中是这样求加速度a的:
a=(Mg+mg-Mg)/(M+M+m)
为什么分母里要M+M..呢?
问题补充：`````
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```````| ``````□ B
`````` | ````` █ P
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``````█ Q
Q,P是砝码,质量都为M
B是小砝码,质量为m
用该装置测定重力加速度g,测出时间t内砝码P通过的距离,利用M,m,t,s写出g的表达式.
答案中是这样求加速度a的:
a=(Mg+mg-Mg)/(M+M+m)
为什么分母里要M+M..呢?
问题补充：`````
````
________________
````` ````| `|
````` ````| `|
````````╭╮
````````╰╯
```````| ``````|
```````| ``````|
```````| ``````|
```````| ``````□ B
`````` | ````` █ P
```````|
``````█ Q
Q,是砝码,质量都为M
是小砝码,质量为m
用该装置测定重力加速度g,测出时间t内砝码P通过的距离,利用M,m,t,s写出g的表达式.
BP系统:(M+m)g-T=(M+m)a
Q系统:T-Mg=Ma
由以上二式可得：
a=(Mg+mg-Mg)/(M+M+m)=mg/(M+M+m)....@
s=v0t+at^2/2,v0=0
a=2s/t^2.........#
由@，#得：g=2s(M+M+m)/mt^2
加速度是整个系统的加速度啊