A metal strip $6.50 \mathrm{~cm}$ long. $0.850 \mathrm{~cm}$ wide, and $0.760 \mathrm{~mm}$ thick moves with constant velocity $\vec{v}$ through a uniform magnetic field $B=$ $1.20 \mathrm{mT}$ directed perpendicular to the $\mathbf{X}$
strip, as shown in Fig. $28-34$. A potential difference of $3.90 \mu \mathrm{V}$ is measured $\mathrm{x}$ between points $x$ and $y$ across the strip. Calculate the speed $v$.