A.16J、16J | B.8J、24J | C.32J、0J | D.48J、-16J |
v1 |
2 |
v1+v2 |
2 |
1 |
2 |
1 |
2 |
1 |
2 |
1 |
2 |
A.1J | B.5J | C.7J | D.无法计算 |
A.Ek2=Ek1 | B.Ek2=2Ek1 |
C.Ek2>2Ek1 | D.Ek1<Ek2<2Ek1 |
A.只要物体的质量发生变化,其动能一定随着变化 |
B.只要物体的速度发生变化,其动能一定随着变化 |
C.物体所受合力不为零时,其动能一定发生变化 |
D.物体所受合力做的功不为零时,其动能一定发生变化 |
A.
| B.
| ||||||
C.
| D.
|
A.mgv | B.
| C.
| D.mgh+
|
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