题目内容
(16分)如图所示,半径
的光滑半圆轨道竖直固定在高
的光滑水平台上,与平台平滑连接,平台长
.可视为质点的两物块
、
束缚在一起,并静止在平台的最右端D点,它们之间有被压缩的轻质弹簧,某时刻突然解除束缚,使两物块
、
具有水平方向的速度,
通过平台到达半圆轨道的最高点A时,轨道对它的压力大小是
,水平抛出后在水平地面上的落在水平地面上的P点,
也落在P点.已知
,
取
.求:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/2014082500232403113309.png)
(1)
在 A时的速度?
(2)P点到D点的水平距离?
(3)解除束缚,使两物块
、
具有的水平方向的速度的大小?.
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323797550.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323813589.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323813537.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323828362.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323844386.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323828362.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323844386.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323828362.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323922650.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323844386.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323969593.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323984273.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324000571.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/2014082500232403113309.png)
(1)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323828362.png)
(2)P点到D点的水平距离?
(3)解除束缚,使两物块
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323828362.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323844386.png)
(1)
(2)
(3)
,![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324172608.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324109568.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324125513.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324140618.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324172608.png)
试题分析: (1)设
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323828362.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324265265.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324312920.png)
解得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324109568.png)
(2)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323828362.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324359291.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324390819.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324406520.png)
设
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324421289.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324452315.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324468258.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324484508.png)
解得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324125513.png)
(3)设弹簧刚解除束缚后,
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323828362.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324546298.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250023245621071.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324140618.png)
设
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323844386.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324655330.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324671327.png)
因
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324686675.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324702533.png)
则
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002324718796.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目