An artificial satellite circling the Earth completes each orbit in 126 minutes. (a) Find the altitude of the satellite.

Explanation:

Time period of rotation

T = 2πR/ V where R is radius of orbit and V is orbital velocity

Orbital velocity V = √ ( GM/R ) , m is mass of the earth .

T = 2πR √R / GM

T² = 4π²R³ / GM

Putting the values

( 126 x 60 )² = 4 x 3.14² x R³ / 6.67 x 10⁻¹¹ x 5.97 x 10²⁴

57.15 x 10⁶ = 39.44 x R³ / 39.82 x 10¹³

R³ = 577 X 10¹⁸

R = 8.325 x 10⁶ m

= 8325 km

Radius of earth = 6400 km

height of satellite = 8325- 6400 = 1925 km .

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