45. A conducting rectangular loop of mass M, resistance R, and dimensions a x b is allowed to fall from rest through a uniform magnetic field which is perpendicular to the plane of the loop. The loop accelerates until it reaches a terminal speed (before the upper end enters the magnetic field). If a = 2.0 m, B = 6.0 T, R= 40 2, and M = 0.60 kg, what is the terminal speed?
(A) 1.6 m/s
(B) 20 m/s
(C) 2.2 m/s
(D) 26 m/s
(E) 5.3 m/s