1. The problem statement, all variables and given/known data

A square metal plate 0.180 m on each side is pivoted about an axis through point O at its center and perpendicular to the plate (Figure 1) .

Calculate the net torque about this axis due to the three forces shown in the figure if the magnitudes of the forces are F1 = 25.0N , F2 = 15.5N , and F3 = 17.0N . The plate and all forces are in the plane of the page. Take positive torques to be counterclockwise.

2. Relevant equations

$\tau=rFsin(\phi)$

3. The attempt at a solution

$rF2+rF3-rF1*sin(45) = .675$, r=.09

Apparently that’s incorrect though, could anyone provide insight as to why?

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