27.45 . The 20.0 cm 35.0 cm rectangular circuit shown in Fig.
E27.45 is hinged along side ab.
It carries a clockwise 5.00-A
current and is located in a uniform
1.20-T magnetic field oriented
perpendicular to two of
its sides, as shown. (a) Draw a
clear diagram showing the
direction of the force that the
magnetic field exerts on each
segment of the circuit (ab, bc,
etc.). (b) Of the four forces you
drew in part (a), decide which
ones exert a torque about the hinge ab. Then calculate only those
forces that exert this torque. (c) Use your results from part (b) to
calculate the torque that the magnetic field exerts on the circuit
about the hinge axis ab.