Avem :
[tex]m=2kg [/tex]
[tex]L=5m [/tex]
[tex]h=3m [/tex]
[tex]F=20N [/tex]
a)
[tex]Gt=?[/tex]
[tex]Gn=? [/tex]
[tex] G^{2} = Gt^{2} + Gn^{2}
[/tex]
[tex]Gt=Gsin \alpha =G* \frac{h}{l} =m*g=10*2* \frac{3}{5} =20* \frac{3}{5} =12N[/tex]
[tex]Gn=G*cos \alpha =G* \frac{d}{l} =2* \frac{4}{5} [/tex]
[tex]cos \alpha = \frac{d}{ l^{2} } [/tex]
[tex] l^{2} = h^{2} + d^{2} [/tex] ⇒ [tex] d^{2} = l^{2} * h^{2} [/tex]
[tex]d^{2} = 5^{2} - 3^{2} =25-9=16[/tex]
[tex]d= \sqrt{16} =4m[/tex]
b)
[tex] F-Ff-Gt=0 [/tex]
[tex]Ff=F-Gt=20N-12N=8N [/tex]
P.s:
Gt= greutatea tangentiala
Gn=greutatea normala
