一物体在直线运动的过程中,先以20米/秒的速度运动了20秒,接着又以40米/秒的速度运动了60秒

2个回答

  • S1=v1t1

    =20m/s*20s

    =400m

    S2=v2t2

    =40m/s*60s

    =2400m

    S =S1+S2

    =400m+2400m

    =2800m

    t =t1+t2

    =20s+60s

    =80s

    v =S/t

    =2800m/80s

    =35m/s

    楼上大意喽!