解：J=mR2=60×(0.25)2 N =3.75kg.m2 t=0w。=2mn=2L×1000 60 =104.7r/s t=5ω=0 0= 0-104.7-20.9r/s2 5 F(l1+12)-N1=0 fR=Ja=HNR N=Ja uR F二1 4,聚=314N 1+12R 结束目录 =3.75kg.m2 t =0 1000 60 ω0 = 2πn= 2π× =104.7 r/s t =5 ω =0 f N N F f l 1 l 2 J mR 2 = = 60×(0.25) 解： 2 ω 104.7 20.9 r/s2 5 0 a t = = = ω0 F (l 1 + l 2) N l 1= 0 f R= J a = m NR l 1 F = l 1 + l 2 mR J a = 314N m N = R J a 结束 目录