1 |
2 |
|
|
1 |
2 |
mv02 |
4qE+2μmg |
0.05×12 |
4×5.0×10-6×1.5×104+2×0.1×0.05×10 |
1 |
2 |
mv12 |
2(qE+μmg) |
0.05×12 |
2×(5.0×10-6×1.5×104+0.1×0.05×10) |
(qE-μmg)d |
2qE-μmg |
(5.0×10-6×1.5×104-0.1×0.05×10)×0.2 |
2×5.0×10-6×1.5×104-0.1×0.05×10 |
1 |
2 |
|
A.电梯地板对物体的支持力所做的功等于
| ||
B.电梯地板对物体的支持力所做的功大于
| ||
C.钢索的拉力所做的功等于MgH+
| ||
D.钢索的拉力所做的功大于MgH+
|
A.重力势能增加了
| ||
B.机械能损失了
| ||
C.动能损失了mgh | ||
D.物体所受的合外力对物体做功为-
|
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