问题
填空题
质量为2kg的物体沿倾角为300的斜面由静止开始下滑，1秒内下滑了2m，则其重力势能改变了________J，1秒末重力的瞬时功率为________w。 （g=10m/s2）
答案
20J 40W
本题考查的是斜面上的重力做功和功率问题。
重力势能的改变等于重力做的功：
，
1秒末重力的瞬时功率为：
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质量为2kg的物体沿倾角为300的斜面由静止开始下滑，1秒内下滑了2m，则其重力势能改变了________J，1秒末重力的瞬时功率为________w。 （g=10m/s2）
20J 40W
本题考查的是斜面上的重力做功和功率问题。
重力势能的改变等于重力做的功：，
1秒末重力的瞬时功率为：
| 完形填空。 | |||
| It is __1__ o'clock. The children __2__ to school by car every day. __3__ today they are going to school on __4__ . It is ten o'clock. Mrs Sawyer usually __5__ at home in the morning,but today she is going __6__ . It is four o'clock in the afternoon. Mrs Sawyer __7__ tea __8__ the living room. But this afternoon she is drinking __9__ in the garden. It is six o'clock in the evening. The children usually do their __10__ . But __11__ they __12__ in the garden. It is nine o'clock. Mr Sawyer usually__13__ his newspaper at night. But he __14__ his newspaper tonight. At the moment he is reading __15__ interesting book. | |||
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