JEE Main2012PhysicsGravitationActual
The mass of a spaceship is 1000 ~kg . It is to be launched from the earth's surface out into free space. The value of ' g ' and ' R ' (radius of earth) are 10 ~m / s ^2 and 6400 ~km respectively. The required energy for this work will be ;
Options
- A6.4 10¹¹ Joules
- B6.4 10^8 Joules
- C6.4 10^9 Joules
- D6.4 10¹⁰ Joules
Correct answer
D. 6.4 10¹⁰ Joules
Step-by-step solution
To launch the spaceship out into free space, from energy conservation, - GMm R + E =0 E = GMm R = ( GM R ^2 ) mR = mgR =6.4 10¹⁰ ~J