Related rates problem:

The beacon on a lighthouse makes one revolution every 20 seconds. The beacon is 300 feet from the nearest point, P, on a straight shoreline. Find the rate at which the ray of light moves along the shore at a point 200 feet from P. (In other words, how fast would you have to drive a car along the shoreline so that you keep up with the light constantly if you were 200 feet along the shoreline from the point P).

Question

Related rates problem:

The beacon on a lighthouse makes one revolution every 20 seconds.  The beacon is 300 feet from the nearest point, P, on a straight shoreline.  Find the rate at which the ray of light moves along the shore at a point 200 feet from P. (In other words, how fast would you have to drive a car along the shoreline so that you keep up with the light constantly if you were 200 feet along the shoreline from the point P).

anonymous · Answer

so, at the point P, the light is traveling at 30(pi) feet/sec, and at 50(pi) feet/sec at the point further inland...should I have to use derivatives to solve this?  Seemed like simple geometry/algebra.

anonymous · Answer

Rate2 = 2(500)(pi)feet/20sec?

anonymous · Answer

misread the question, and changed it...