Question

A satellite is revolving round the earth. Its kinetic energy is $E_k$ . How much energy 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

The correct option is A $2E_k$

$\frac{E_{k_{escape}}}{E_{k_{revolution}}}=\frac{\frac{1}{2}m{V}_e^2}{\frac{1}{2}m{V}_0^2}=(\frac{V_e}{V_0}{)}^2=2$

$E_{kescape}=E_{k_{revolution}}\left(2\right)=2E_k$