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)`.

Options

A. `11.2 km//s`
B. `8 km//sec`
C. `3.2km//sec`
D. `1.414xx8km//sec`

Answer

C

Explanation

`V_(e)=11.2km//s`
`(mv'^(2))/R=(GMm)/(R^(2))`
`v'^(2)=(GM)/(R^(2))R`
`v'=sqrt(10xx6400000)`
`v'=8km//s`
`:.` Additional velocity `=(11.2-8)=3.2km//s`