3 |
3 |
1 |
2 |
v | 21 |
1 |
2 |
v | 20 |
2 |
v | 22 |
v | 21 |
1 |
2 |
v | 22 |
1 |
2 |
v | 22 |
1 |
2 |
v | 21 |
′ | 21 |
v | 20 |
′ | 21 |
1 |
2 |
′ | 21 |
1 |
2 |
′ | 21 |
1 |
2 |
′ | 22 |
v
| ||
R |
2 |
2 |
1 |
4 |
A.小球不可能做圆周运动 |
B.小球和弹簧组成的系统机械能增加 |
C.小球重力势能的减少量等于重力对小球做的功 |
D.小球的电势能的减少量等于小球动能的增量减去弹簧弹力对小球做的功 |
A.v′>v | B.v′=v | C.v′<v | D.不能确定 |
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