A square loop of wire with side length L and resistance R is moved at constant speed v across a uniform magnetic field confined to a square region whose sides are twice the length of those of the square loop (Fig. 29.39).(a) Graph the external force F needed to move the loop at constant speed as a function of the coordinate x from x = ??2L to x = + 2L. (The coordinate x is measured from the center of the magnetic-field region to the center of the loop. It is negative when the center of the loop is to the left of the center of the magnetic-field region. Take positive force to be to the right.)(b) Graph the induced current in the loop as a function of x. Take counterclockwise currents to be positive.

-2L K 2L X X -L -21- X X X X X 0 x x X X X L 1 2L -X