Solution to task 459 from Chertov´s for extramural stud

459. A flat circuit with a current I = 50 A is located in a uniform magnetic field (B = 0.6 T) so that the normal to the circuit is perpendicular to the lines of magnetic induction. Determine the work done by the field forces with a slow rotation of the contour about the axis lying in the plane of the contour at an angle α = 30 °.