Thanks to the research that folks at the Hawkion facility were able to do on the EM-boar tigers, the people of Lakeview have been able to set up a scientifically supported protection system. They have installed a giant magnet into the cliffs nearby, and it is aligned in such a way that there is a constant (practically speaking) $5 \text{ mT}$ magnetic field directed into the ground near Lakeview and the surrounding area. The hope is that the field will ward off the EM-boar tigers and keep the people of Lakeview safe.

However, there is a dilemma that has emerged. Local inventor and superstitious person Manny Hallabero is starting to create a fuss around town because he believes the magnetic field is going to destroy his car. He has been driving around with a voltmeter attached to his engine and he claims there is a potential difference across the engine when he's driving fast. Once, he said, there was a potential difference of $0.15 \text{ V}$. He is worried that if the voltage across his engine reaches much higher, it will surely be destroyed and he could end up in danger. Out of the goodness of your heart, you wish to assuage Manny's worries and explain to him why the potential difference exists. You should also provide some guidelines for Manny to make sure he doesn't cause the potential difference to exceed $0.15 \text{ V}$.