Question

A space ship is launched into a circular orbit close to the surface of the earth. The additional velocity now imparted to the spaceship in the orbit to overcome the gravitational pull is

• A. $11.2\, km\, s ^{-1}$
• B. $8\, km\, s ^{-1}$
• C. $3.2\, km\, s ^{-1}$
• D. $1.414 \times 8\, km\, s ^{-1}$

Answer 1

Answer: (C)

$v_{e}=11.2\, km / s$
$\frac{m v^{'2}}{R}=\frac{G M m}{R^{2}}$
$v^{'2}=\frac{G M}{R^{2}} R=8\, km / s$
Therefore, the additional velocity $=(11.2-8)=3.2\, km / s$