Q134 / 160 · TS EAMCET 2018 (07 May Shift 1) · Physics
An artificial satellite of mass $m$ revolves around the earth at a height $h$ with a speed $v$. How much power (energy per second) will it require to keep itself moving with constant speed in the orbit of radius $r$ ?
- A$\frac{m v^3}{r}$
- B$\frac{1}{2} m v^2$
- C$\frac{6 m M_e}{\left(R_e+b\right)}$
- Correct answerD0
Solution
Speed of satellite is constant, so by workenergy theorem,
$$
\begin{aligned}
& W=K_f-K_{\dot{i}} \\
& W=\frac{1}{2} m v^2-\frac{1}{2} m v^2 \\
& W=0
\end{aligned}
$$
As, work on satellite is zero, so power required will also be zero, i.e. $P=\frac{W}{t}=0$
Hence, the correct answer is option: 'D'.