Chapter 13, Problem 90CP

A rectangular copper loop of mass 100 g and resistance $0.2\Omega$ is in a region of uniform magnetic field that is perpendicular to the area enclosed by the ring and horizontal to Earth's surface (see below). The loop is let go from rest what it is at the edge of the nonzero magnetic field region. (a) Find an expression for the speed when the loop just exits the region of uniform magnetic field. (b) If it was let go at t = 0, what is the tune when it exits the region of magnetic field for the following values, $a=25cm,b=50cm,B=3T,g=9.8m/s^2$ ?Assumethat the magnetic field of the induced current is negligible compared to 3 T.