A circular ring with area 4.45 cm2 is carrying a current of 12.5 A the ring is free to rotate about a diameter. The ring, initially at rest, is immersed in a region of uniform magnetic field given by B = (1.15 X 10-2 T) (12i + 3j - 4k). The ring is positioned initially such that its rnagne1ic moment is given by A = µ ( -0.800i + 0.600j) , where µ is the (positive) magnitude of the magnetic moment. The ring is released and turns through an angle of 90.0°, at which point its magnetic moment is given by µf= -µk.
(a) Determine the decrease in potential energy.
(b) If the moment of inertia of the ring about a diameter is 8.50 X 10-7 kg. m2, determine the angular speed of the ring as it passes through the second position.