(a) Find the radius of the circular orbit of a satellite moving with an angular speed equal to the angular speed of earth’s rotation.

(b) If the satellite is directly above the North Pole at some instant, find the time it takes to come over the equatorial plane.


Mass of the earth = 6 × 1024 Kg.


Given, the angular speed of satellite is equal to the rotation of earth.

Therefore, time period of revolution of satellite,


Let the radius of the orbit be


We know,







(b) To travel from pole to equator, the satellite travels a quarter of the orbit. A complete revolution takes 24 hours, therefore a quarter of revolution would take



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