沿天花板方向,Fsin37-mgsin37-f=ma.即:6-3-f=3-f=0.5a.垂直斜面方向:Fcos37=mgcos37+N.即:8=4+N,则天花板向下压力N=4N.则f=μN=2N.则刷子加速度a=2m/s^2.
s=0.5at^2,推到顶端所需时间t=sqrt(2s/a)=sqrt(4)=2s
沿天花板方向,Fsin37-mgsin37-f=ma.即:6-3-f=3-f=0.5a.垂直斜面方向:Fcos37=mgcos37+N.即:8=4+N,则天花板向下压力N=4N.则f=μN=2N.则刷子加速度a=2m/s^2.
s=0.5at^2,推到顶端所需时间t=sqrt(2s/a)=sqrt(4)=2s