4.64
m*0=0=mg*sin(alpha)-mg*cos(alpha)*мю+F1
m*0=0=-mg*sin(alpha)-mg*cos(alpha)*мю+F2
************
F1=-mg*sin(alpha)+mg*cos(alpha)*мю
F2=mg*sin(alpha)+mg*cos(alpha)*мю
************
a)
sin(alpha)=(F2-F1)/(2*mg)=(12-2)/(2*1*10)=
0,5
alpha = 30 градусов=pi/6
************
б)
F1=-mg*sin(alpha)+mg*cos(alpha)*мю
мю=(F1+mg*sin(alpha))/(mg*cos(alpha))=(2+1*10*sin(pi/6))/(1*10*cos(pi/6))=
0,80829
~ 0,81
***********
в)
m*a=mg*sin(alpha)-(mg*cos(alpha)-F*sin(alpha))*мю+F*cos(alpha)
a=g*sin(alpha)-(g*cos(alpha)-F/m*sin(alpha))*мю+F/m*cos(alpha)=
=10*sin(pi/6)-(10*cos(pi/6)-2/1*sin(pi/6))*0,81+2/1*cos(pi/6) м/с^2=
= 0,527245 м/с^2 ~
0,53 м/с^2