A satellite is orbiting the earth. It's orbital radius is reduced to half of its initial value then the…

A satellite is orbiting the earth. It's orbital radius is reduced to half of its initial value then the change in its total energy is
  1. $100 \%$
  2. $75 \%$
  3. $50 \%$
  4. $25 \%$

Solution

Total energy of satellite revolving around the earth, $ \begin{aligned} & E=\frac{-G M_t m}{r} \\ & \text { i.e } \quad E \propto \frac{1}{r} \\ & \Rightarrow \quad \frac{E_2}{E_1}=\frac{r_1}{r_2} \\ & =\frac{r_1}{\frac{r_1}{2}} \quad\left(\therefore \text { Given } r_2=\frac{r_1}{2}\right) \\ & =2 \\ & E_2=2 E_1 \\ & \end{aligned} $ $\therefore \%$ change in total energy of satellite $ \begin{aligned} & =\frac{E_2-E_1}{E_1} \times 100 \\ & =\frac{2 E_1-E_1}{E_1} \times 100=100 \% \end{aligned} $

Asked in: AP EAMCET 2022 (06 Jul Shift 2)

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