Question

Urgent! Problema simpla de fizica​

Answer 1

$|L_{F_f}|=8 J\\|L_{F_f}|=F_f*d=\mu Nd=\mu mgcos\alpha d=>\mu=\frac{|L_{F_f}|}{mgcos\alpha d}=\frac{8}{4*10*\frac{1}{2}*4 }=\frac{8}{80}=>\mu= 0,1$