寒清默默
幼苗
共回答了198个问题 举报
1.P=FV,F=P/V=1.2×104 /20N=600N
2.机械效率=Gh/FS=80%,F=Gh/(sx80%)=1125N,V=P/F=10.66M/S
3.10Km,平路,t=s/v=500s,w1有=pt=6x106j,w1总=6x106/(45%)=1.3x107j,90Km,t=s/v=9000s,
w有2=pt=1.2×104 x9000j=1.08x108j,w总2=1.08x108j/(36%)=3x108j,w总=w1总+w总2=3.13x107j
m=w/q=
1年前
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