Chapter 29 Problem 33

Problem

A conducting rod rests on two long frictionless parallel rails in a magnetic field ${\vec {B}}$ ( $\perp$ to the rails and rod)

(a) If the rails are horizontal and the rod is given an initial push, will the rod travel at constant speed even though a magnetic field is present?

(b) Suppose at $t=0$, when the rod has speed $v=v_{0}$ , the two rails are connected electrically by a wire from point a to point b. Assuming the rod has resistance $R$ and the rails have negligible resistance, determine the speed of the rod as a function of time. Discuss your answer.