[tex]T = \frac{40\sqrt{3}}{3} e N = \frac{20\sqrt{3}}{3} \\
T_{x} = T . cos60^{o} = \frac{T}{2} \\
T_{y} = T . sen60^{o} = \frac{\sqrt{3}T}{2} \\
Sendo \sum{F} = 0
T_{x} = P
\frac{\sqrt{3}}{2}T = 20 \\
T = \frac{40}{\sqrt{3}} = \frac{40\sqrt{3}}{3}N \\
N_{A} = T_{x} \\
N_{A} = \frac{T}{2} \\
N_{A} = \frac{\frac{40\sqrt{3}}{3}}{2}}
N_{A} = \frac{40\sqrt{3}}{6} \\
N_{A} = \frac{20\sqrt{3}}{3} \\
N_{A} = 11,53N \\
[/tex]