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一人从雪坡上匀加速下滑,他依次通过abc三个标志旗,已知ab =" 6" m,bc =" 10" m,人通过abbc所用时间都等于2 s,则人过abc三个标志旗的速度分别是( )
A.vA =" 2" m/s,vB =" 3" m/s,vC =" 4" m/s
B.vA =" 2" m/s,vB =" 4" m/s,vC =" 6" m/s
C.vA =" 3" m/s,vB =" 4" m/s,vC =" 5" m/s
D.vA =" 3" m/s,vB =" 5" m/s,vC =" 7" m/s
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