The forces on the arms BC and DA are equal, opposite, and act along
the axis of the coil, which connects the centres of mass of BC and DA Being collinear along the axis they cancel each other, resulting in no net
force or torque The forces on arms AB and CD are F1 and F2 They too
are equal and opposite, with magnitude,
F1 = F2 = I b B
But they are not collinear