题目内容
(8分)如图甲所示,电荷量为q=1×10-4C的带正电的小物块置于粗糙绝缘水平面上,所在空间存在方向沿水平向右的电场,电场强度E的大小与时间的关系如图乙所示,物块运动速度与时间t的关系如图丙所示,取重力加速度g=10m/s2。
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250035223509452.png)
求:(1)前2秒内电场力做的功;
(2)物块的质量。
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250035223509452.png)
求:(1)前2秒内电场力做的功;
(2)物块的质量。
(1)7J(2)0.5kg
试题分析:(1)0-1s内的位移
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003522366697.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003522381623.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003522397683.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003522412704.png)
前2秒内电场力做的功
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003522428697.png)
(2) 0-1s内的加速度
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003522459877.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003522475703.png)
1s-2s内物体匀速有
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003522490547.png)
得
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003522506619.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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