A rod of mass 0.720 kg and radius 6.00 cm rests on two parallel rails that are d = 12.0 cm apart and
= 45.0 cm long. The rod carries a current of I
A in the direction shown and rolls along the rails without slipping. A uniform magnetic field of magnitude 0.500
T is directed perpendicular to the rod and the rails. If it starts
from rest, what is the speed of the rod as it leaves the rails?