A space ship of mass $2\times {10}^4 \mathrm{kg}$ is launched into a circular orbit close to the earth surface. The additional velocity to be imparted to the space ship in the orbit to overcome the gravitational pull will be (if $g=10 \mathrm{m} {\mathrm{s}}^{-2}$ and radius of earth $=6400 \mathrm{km}$ ):

• A

  $11.2(\sqrt{2}-1) \mathrm{km} {\mathrm{s}}^{-1}$
• Correct answer
  B

  $8(\sqrt{2}-1) \mathrm{km} {\mathrm{s}}^{-1}$
• C

  $7.9(\sqrt{2}-1) \mathrm{km} {\mathrm{s}}^{-1}$
• D

  $7.4(\sqrt{2}-1) \mathrm{km} {\mathrm{s}}^{-1}$

Hence, the correct answer is option: 'B'.