🧲 Eddy-Current Brake Disc: Torque Curve, Coast-Down and Heating (2D face view)

Face view of a metal disc spinning through a magnet gap: eddy currents make a braking torque that grows with B squared and speed, then rolls off, and all the lost energy heats the disc. Same model as the 3D page, with coast-down, energy, terminal-speed and heating checks.