Question

Let the escape velocity of a body kept at surface of a planet is u.If it is projected at a speed of 200% more than the escape speed, then the speed in interstellar space will be

Answer 1

If a body is projected with speed Vi = KVe (k>1), the final intersteller speed is (√k²-1)Ve 
if Vi = KVe (k<1) directed vertically upward the maximum height from centre of  earth of radius R attained by the body is  r = R /1-K²
and hence its maximum height from surface of earth is H=  r-R = (R /1-K²) - R
= RK²/1-K²
By this method now velocity is V+2V = 3V
So k=3
Finally intersteller  speed = (√k²-1) viz. √8 = 2√2

Answer 2

Hey! They say i hav to write 20 charecters atleast ! Thus ! Sorry to bore u if ur reading this ! But u know what picture at the bottom is the answer