I did part a) of this question but got stuck when it comes to part b). It asks how the induction of an emf causes the vehicle to slow down. When the aluminium disc rotates, this conductor cuts through a magnetic field so there is an emf induced. So this induced emf means that there is an induced current (the eddy currents). Is kinetic energy converted into the internal energy of the aluminium disc? So is this what slows down the vehicle? However, there are areas in the mark scheme that I didn't understand: 1) (I^2)R losses - why is there power loss? 2) (direction of) force opposes motion & opposing magnetic fields - eddy currents are not the result of back emf, right?