Chapter 11 - Rotational Dynamics and Static Equilibrium - Problems and Conceptual Exercises - Page 366: 2

$F=3.8N$

The magnitude of torque is equal to $$\tau=rFsin\theta$$ If the force is applied perpendicular to the radius, the torque becomes $$\tau=rF$$ Solving for $F$ yields $$F=\frac{\tau}{r}$$ To find the force from the hinge, use values of $\tau=1.23 N \times m$ and $r=32cm=0.32m$. $$F=\frac{1.23N \times m}{0.32m}=3.8N$$