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A lighthouse is located on a small island 5 km away from the nearest point p on a straight shoreline and its light makes two revolutions per minute. how fast is the beam of light moving along the shoreline when it is 1 km from p? (round your answer to one decimal place.)

Respuesta :

shinmin

The distance starting from the point to the lighthouse would be regarded as the hypotenuse.

And also will be the radius of the circle the beam of light is generating at that point. 


So get the radius first

r = sqrt (1^2 + 5^2)

r = 5.099 km


find the circumference:

C = 2*pi * 5.099 km

C = 2 * 16.01898094

C = 32.04 km


Then find the speed in km/sec

One revolution: 60/2 = 30 sec per revolution

Speed = 32.04 km/30 sec

S = 1.068 km/sec is the speed of light

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