Question

In a two stage launch of a satellite, the first stage brings the satellite to a height of 150 km and the 2^nd stage gives it the necessary critical speed to put it in a circular orbit. Which stage requires more expenditure of fuel ? Given mass of earth = 6.0 × 10²⁴ kg, radius of earth = 6400 km.

Answer 1

Work done on satellite in first stage = W₁ = PE at 150 km – PE at the surface

Work done on satellite in 2nd stage = W₂ = energy required to give orbital velocity v₀ 

W₂ > W₁, so second stage requires more energy.