A rotating beacon is located 2 miles out in the water. Let A be the point on the shore that’s closest to the beacon. As the beacon rotates at 10 revolution per minute, the beam sweeps down the shore once each time it revolves. Assume that the shore is straight. How fast is the point where the beam hits the shore moving at an instant when the beam is lighting up a point 2 miles downshore from point A?
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