4.65
m*0=0=mg*sin(alpha)-mg*cos(alpha)*мю-F1
m*0=0=-mg*sin(alpha)-mg*cos(alpha)*мю+F2
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F1=mg*sin(alpha)-mg*cos(alpha)*мю
F2=mg*sin(alpha)+mg*cos(alpha)*мю
************
a)
sin(alpha)=(F1+F2)/(2*mg)=(3,26+6,74)/(2*1*10)=
0,5
alpha = 30 градусов=pi/6
************
б)
F1=mg*sin(alpha)-mg*cos(alpha)*мю
мю=(mg*sin(alpha)-F1)/(mg*cos(alpha))=(1*10*sin(pi/6)-3,26)/(1*10*cos(pi/6))= 0,2
***********
в)
m*a=-mg*sin(alpha)-(mg*cos(alpha)+F*sin(alpha))*мю+F*cos(alpha)
a=-g*sin(alpha)-(g*cos(alpha)+F*sin(alpha)/m)*мю+F*cos(alpha)/m=
=-10*sin(pi/6)-(10*cos(pi/6)+10*sin(pi/6)/1)*0,2+10*cos(pi/6)/1=
0,928203 м/с^2 ~
0,93 м/с^2