ExamBro
ExamBro
JEE Mains · Physics · STD 11 - Gravitation
  • JEE Mains 2024
  • Hard
  • MCQ

At what distance above and below the surface of the earth a body will have same weight? (take radius of earth as \(R\).)

Pick an option to check your answer.
Verified Solution

Answer & Solution

Correct Answer

(D)  \(\frac{\sqrt{5} \mathrm{R}-\mathrm{R}}{2}\)

Step-by-step Solution

Detailed explanation

\( g_p=\frac{g R^2}{(R+h)^2} \)

\( g_q=g\left(1-\frac{h}{R}\right) \)

\( g_p=g_q \)

\( \frac{g}{\left(1+\frac{h}{R}\right)^2}=g\left(1-\frac{h}{R}\right) \)

\( \left(1-\frac{h^2}{R^2}\right)\left(1+\frac{h}{R}\right)=1\)

Take \(\frac{\mathrm{h}}{\mathrm{R}}=\mathrm{x}\)

So

\( \mathrm{x}^3-\mathrm{x}+\mathrm{x}^2=0 \)

\( \mathrm{x}=\frac{\sqrt{5}-1}{2} \)

\( \mathrm{~h}=\frac{\mathrm{R}}{2}(\sqrt{5}-1)\)

Same subject
Explore more questions on app