Question

A communications satellite is in a synchronous orbit that is 3.61×107 m directly above the equator. The satellite is located midway between Quito, Equador, and Belem, Brazil, two cities almost on the equator that are separated by a distance of 3.87×106 m. Calculate the time it takes for a telephone call to go by way of satellite between these cities. Ignore the curvature of the earth.

Answer 1

The total distance traveled by signal is s.
So that the distance between Belem (or Quito) to satellite iss / 2 .
Therefore we can write
    s / 2 = √ [ (h)² + (d / 2)² ]
                             = √ [ (3.61 x 10⁷)² + (3.87x 10⁶ / 2)² ]
                             = 3.615 x 10⁷ m
        ==>       s = 7.23 x10⁷ m
The time taken by electromagnetic wave to travel a totaldistance s is
                  t = s / c
                    = 7.23 x 10⁷ / 3 x 10⁸
    = 0.241 sec