A spaceship is launched into a circular orbit close to the earth's surface . What additional velocity has now to be imparted to the spaceship in the orbit to overcome the gravitational pull. Radius of earth `= 6400 km`, `g = 9.8m//s^(2)`.

Explanation

Orbital velocity close to the earth's surface
`upsilon_(0) = sqrt(gR)`
Escape velocity, `upsilon_(e) = sqrt(2gR)`
`= (1.414 - 1) sqrt(9.8xx (6.4 xx 10^(6))`
`= 3.28 xx 10^(3) ms^(-1) = 3.28 km s^(-1)`