设汽车质量m,制动距离为s1,摩擦系数n.
动能E=1/2mV^2=555.5m(j);
制动距离s1=E/F=E/(mgn)=555.5m/(m*10*0.4)=138.8(m);
s=s1+Vt=138.8+120000/3600*0.5=155.5(m).
设汽车质量m,制动距离为s1,摩擦系数n.
动能E=1/2mV^2=555.5m(j);
制动距离s1=E/F=E/(mgn)=555.5m/(m*10*0.4)=138.8(m);
s=s1+Vt=138.8+120000/3600*0.5=155.5(m).