Chapter 30, Problem 59EAP

FIGURE P30.59 shows a U-shaped conducting rail that is oriented vertically in a horizontal magnetic field. The rail has no electric resistance and does not move. A slide wire with mass m and resistance R can slide up and down without friction while maintaining electrical contact with the rail. The slide wire is released from rest.

a. Show that the slide wire reaches a terminal speed $v_{\text{term}}$ and find an expression for $v_{\text{term}}$.

b. Determine the value of $v_{\text{term}}$ if $l=\text{2}0$ cm, $m=10g$ , $R=0.\text{1}0\Omega$ , and $B=0.\text{5}0\text{ T}$ .