Answer
$\approx 17.32 \ N \ m$
Work Step by Step
The magnitude of torque is $|\tau|=|r \times F| =|r||F| \sin \theta$
The angle is acute, so $\theta =60^{\circ}$
Plug in the data and we have:
$|\tau|=|r \times F| =(0.4)(50) \sin 60^{\circ}$
or, $|\tau| \approx 17.32 \ N \ m$
