(1)f=μmg=0.3×3×10=9N
a=μg=3m/s²
t加速=v/a=2s
x=1/2at²=1/2×3×4=6m
Wf=fx=9×6=54J
(2)t加速=v/a=8/3s
x=1/2at²=1/2×3×64/9=32/3m>10m
Wf=f×L=9×10=90J
(1)f=μmg=0.3×3×10=9N
a=μg=3m/s²
t加速=v/a=2s
x=1/2at²=1/2×3×4=6m
Wf=fx=9×6=54J
(2)t加速=v/a=8/3s
x=1/2at²=1/2×3×64/9=32/3m>10m
Wf=f×L=9×10=90J