We're heading north to drive to college and have rented a U-Haul trailer for our stuff. Earth's magnetic filed is about 5.0 x 10^-5 T (vertical component and pointing toward Earth's center), and we are driving the legal speed limit of 65 MPH. The trailer is 5feet wide (axle separation). What is the emf induced between the two sides of the trailer, and is it the driver or passenger side that the positive charge accumulates?