A.绳子拉力不断减小 | B.绳子拉力大小不变 |
C.船的浮力减小 | D.船的浮力增大 |
A.物体做匀速圆周运动 |
B.3 s内物体的位移大小是16.5 m |
C.3 s末物体的速度大小是7 m/s |
D.3 s末物体的速度大小是5 m/s |
A.10N | B.35N | C.50N | D.70N |
3 |
A.4m/s | B.2
| C.2m/s | D.4
|
A.5N,3N | B.7N,2N | C.12N,3N | D.12N,0 |
A.共点力2N、5N、9N | B.共点力21N、30N、50N |
C.共点力9N、18N、8N | D.共点力20N、30N、60N |
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