Kai is filming a train pass by for a movie they are making. The train tracks run east to west, and Kai is standing 50 feet due south of the nearest point P on the tracks. Kai begins filming (time t = 0) when the train is at the nearest point P, and rotates their camera to keep it pointing at the train as it travels west at 20 feet per second. Find the rate at which Kai is rotating their camera when the train is 120 feet from them (in a straight line). Exact answers only. No decimal approximations. Start by drawing and labeling a picture.