(1).a=V/t=0.5m/s2 (2)s=1/2at2=900m (3)F-f=ma ∴F=1750N
0.5m/s² 900m 1750N
(1)a=V/t=0.5m/s2(2)s=1/2at2=900m(3)F-f=ma ∴F=1750N
(1)a=30/60=0.5 (2)v^2=2as 得S=900m (3) F-f=ma 得F=1750N
