用500n水平恒力将质量为250nkg的物体，从静止开始沿水平地面推动50m历时10s。若物

s=at²/2, s=50m, t=10s
a=1m/s
F'=250N, F=500N
f=250N
μ=f/G=f/mg=250N/(250kg由S=1/2at^2,可得:a=2S/t^2=2*50/10^2=1m/s^2
由F-f=ma,可得:f=F-ma=500-250*1=250N *10N/kg)=0.1 1/2at²=50，a=1
F-f=ma，f=250

s=at²/2, s=50m, t=10s
a=1m/s
F'=250N, F=500N
f=250N
μ=f/G=f/mg=250N/(250kg*10N/kg)=0.1

由S=1/2at^2,可得:a=2S/t^2=2*50/10^2=1m/s^2
由F-f=ma,可得:f=F-ma=500-250*1=250N

1/2at²=50，a=1
F-f=ma，f=250