The following code generated the picture above. The light can be pinpoint directed from the center of the ellipse to any point along the perimeter of the ellipse and the light is rotating at a speed of 60 rpm. The light starts facing diametrically away from the screen and rotates clockwise. Describe the motion of the light which reaches the screen as a function of time t during the first revolution of the light. Offer a plot to convince yourself that your mathematical description is right.
Extensions Have the tank of water have a sinusoidal front to it between the screen and the light.
We enter the equation of the top half of the ellipse. A plot is reassuring. We use Snell's Law to compute the angle of refraction at this same point on the perimeter of the ellipse. Again a plot is reassuring. We make some plots leading to a time animation of the light beams as well as the points on the perimeter of the ellipse and the screen.