This interactive phasor page allows you to control the values of a rotating phasor and see a visualization of each change that is done. You can control: one, pos/neg, two, beats, delta, sawtooth, square, triangle, time,...

A unit that discusses some physics: the lever, density, buoyancy, the continuity equation, dynamic similarity, the difference between units and dimensions, the Reynolds number, the Froude number, and the Mach number....