Question

A sky laboratory of mass $2\times {10}^{3}Kg$ is raised from a circular orbit of radius 2R to a circular orbit of radius 3R. The work done is (approximately):

• A. ${10}^{16}J$
• B. $2\times {10}^{10}J$
• C. ${10}^{6}J$
• D. $3\times {10}^{10}J$

Answer 1

The correct option is B $2\times {10}^{10}J$

$W=U_2-U_1=\frac{+Mm}{3R}(-\frac{GMm}{2R})=\frac{GMm}{6R}=\frac{mgR}{6}$
$=W=\frac{2\times {10}^3\times 9.8\times 6.4\times {10}^6}{6}=2\times {10}^{10}J$