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#40? 40. The earth has a radius of 6.38 x 10^6 m and turns on its axis once ever

ID: 1293464 • Letter: #

Question

#40? 40. The earth has a radius of 6.38 x 10^6 m and turns on its axis once every 23.9 h. (a) What is the tangential speed (in m/s) of a person living in Ecuador, a country that lies on the equator? (b) At what latitude (i.e., the angle theta in the drawing) is the tangential speed one-third that of a person living in Ecuador? 41. ssm A baseball pitcher throws a baseball horizontally at a linear speed of 42.5 m/s(about 95 mi/h). Before being caught, the baseball travels a horizontal distance of 16.5 m and rotates through an angle

Explanation / Answer

(a)

The tangential speed of the person is,

         v = 2(pi)r/T

            = 2(pi)(6.38x106 m) / (23.9 h)(3600 s/ 1h)

            = 466 m/s

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The required angle can be calculated as follows:

              theta = cos-1(r' /r)

                      = cos-1 (1/3)

                      = 70.5o