Kibble Balance: 2D Beam & Flux Trace

This is the 2D side-view counterpart to the 3D Kibble-balance simulator, built from its own independent numerics rather than a flattened render of the 3D rig. A beam pivots under a real damped rotational equation of motion — J·θ″ = (B·I·L − m·g)·arm − c·θ′, integrated every frame — so nulling the current with the Servo Null button produces a genuine, visibly damped settling motion rather than an instant snap. In the velocity phase, the same coil sweeps through the field and the simulator tracks its flux linkage Φ(t) = B·L·y(t) directly, then numerically differentiates it frame by frame to recover the induced voltage via Faraday's law — a computation that happens to reproduce U = B·L·v exactly, but is derived rather than assumed. A scrolling strip chart beneath the beam — a view with no counterpart in the 3D scene — plots beam angle while weighing or the differentiated voltage while sweeping, so you can read the physics as a live trace as well as watch the beam and coil move. Combine a recorded current and a recorded voltage to recover the test mass, with the unknown geometric factor B·L cancelling out exactly as it does in a real instrument.