Say if an iron disk slides down a non ferromagnetic conductor ramp and we get a certain time. And then we have an iron disk with the same mass but MAGNETIZED slide down the same ramp and get a longer time (because of of magnetic braking). The calculated acceleration of the MAGNETIZED disk will be smaller. We then take these velocities and plug them into an energy equation (ET1 = ET2 or something like that) to find the energy lost. We use this to find 2 different energy lost amounts, and then use Wff = Ff(d)(cos180) to find the force of friction. We will get a different force of friction for each disk because they each had a different energy lost amount. Now here is the question: if I know the normal force and stick the force of friction into the coefficient equation: Ffk = μkFn, I will get different coefficients for each disk. Why is that? I thought the coefficient depended on the material and the surface? In this case both are the same. Unless being magnetized changes the coefficient? All help is appreciated!!