题目内容
小球沿斜面滚下,依次经过A、B、C三点,已知AB="6" m,BC="10" m,球通过AB、BC路程所用时间均为2 s,则小球经过A、B、C三点时的瞬时速度是
- A.vA="2" m/s,vA ="3" m/s,vC="4" m/s
- B.vA="2" m/s,vA ="4" m/s,vC="6" m/s
- C.vA="3" m/s,vA ="4" m/s,vC="5" m/s
- D.vA="3" m/s,vA="5" m/s,vC="7" m/s
B
vB=m/s="4" m/s
Δs=BC-AB=at2a="1" m/s2
vB=vA+atvA=vB-at="2" m/s
vC=vB+at="4" m/s+1×2 m/s="6" m/s
vB=m/s="4" m/s
Δs=BC-AB=at2a="1" m/s2
vB=vA+atvA=vB-at="2" m/s
vC=vB+at="4" m/s+1×2 m/s="6" m/s
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