Apparently, that's how a lot of car speedometers work... but I don't understand how a rotating magnet inside a coil (or any conductive material, really) can induce a current in the coil. I can understand how pushing a magnet in and out through a coil can induce current, because Flux = Area * Magnetic field strength * sin θ, and the magnetic field acting upon the coil is becoming stronger. But I don't see how spinning a magnet inside a coil is going to do anything, much less create eddy currents to oppose the spinning and somehow create a torque. Could someone refer me to a video or an image of some kind? I've tried to figure this out but nothing really comes to mind.