Question

As you have learnt in the text, a geostationary satellite orbits the Earth at a height of nearly 36,000 km from the surface of the Earth. What is the potential due to Earth's gravity at the site of this satellite? (Take the potential energy at infinity to be zero). Mass of the Earth = 6.0 x 10²⁴ kg, radius = 6400 km

Answer 1

Distance of satellite from the centre of the earth

= R + r + x = 6400 + 36,000

= 42400 km = 4.24 x 10⁷ m

Using potential, V = -Gm/r, we get

V = (-){(6.67 x 10^-11) x (6 x 10²⁴)}/{(4.24 x 10⁷)} = -9.44 x 10⁶ J kg^-1