A space-ship is put into a circular orbit close to Earth's surface. What additional velocity must be imparted to the ship so that it is able to escape the gravitational pull of Earth(approximately)? (R=6400km,g=9.8 ms2)
3.3 km/s
The orbital velocity in a circular orbit close to Earth is:
v = √gR.
The velocity required to escape is ve = √2gR
ve − v = (√2 − 1) √gR
Hence additional velocity required is: ve − v = 0.414 × √9.8×6400×103 = 3278.71 ms = 3.278 kms.