Question

A satellite is revolving round the earth. Its kinetic energy is , How much energy $E_k$ is required by the satellite such that it escapes out of the gravitation field of earth

• A. $2E_k$
• B. $3E_k$
• C. $\frac{E_k}{2}$
• D. infinity

Answer 1

Answer: (A)

$\frac{ E _{ k _{\text {esape }}}}{ E _{ k _{\text {rerclutian }}}}=\frac{\frac{1}{2} mV _{ e }^{2}}{\frac{1}{2} mV _{0}^{2}}=\left(\frac{ V _{ e }}{ V _{0}}\right)^{2}=2$
$E _{\text {kescape }}= E _{ k _{\text {reralيtism }}}(2)=2 E _{ k }$