If a permanent magnet rod enters a coil of wires at a certain speed will the permanent magnet slow down? I'm trying to build a generator of some sort. So i need to know is my logic sound. I'll give you scenario. Scenario: The permanent magnet slides into the coil at a speed of 3meters/second. What will the speed of the magnet be after exiting the coil? Permanent magnet parameters Mass : 2kg Strength : 2000Gauss or 0.2Tesla Area : 0.008m2 Wire Coil Parameters Turns : 20000 Resistance : 50 Ohm Length of Coil : 3meters Thus the energy contain in the magnet moving at 3ms-1 is = 9joules E=1/2 mv^2 E=(1/2)(2)(3^2) E=9Joules So using faradays law, the power generated by the magnet passing thru the coil of wire : V= (-N)(BA/t) V = voltage N = Turns B = Flux (in tesla) t = Round per second A = Surface Area of permanent magnet Note : I will reduce the flux strength to 0.1tesla because the coil will be approximately 2mm from the magnet V = (-20000)(0.1*0.008*/1) V = 16Volts Thus the current generated is I=V/R I = 16V / 50ohm I = 0.32amps Thus power generated is Power = VI Power = 16V * 0.32amps Power = 5.12Watts or joule per second Thus the speed of the permanent magnet exiting the coil is 9joules – 5.12 joules = Kinetic Energy Remaining 3.88 = (1/2)(2)(v ^2) v = √(3.88*2/2) v = 1.96ms-1 Is this logic and calculation correct??