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The weight of a body at the surface of earth is 18 N. The weight of the body at an altitude of 3200 km above the earth's surface is (given, radius of earth Re=6400\; km)

Option: 1

8 N


Option: 2

4.9 N


Option: 3

9.8 N


Option: 4

19.6 N


Answers (1)

best_answer

Weight on earth surface \mathrm{W}=\mathrm{mg}=18 \mathrm{~N}

Above earth surface \Rightarrow \mathrm{W}_2=\mathrm{m} \frac{\mathrm{GM}}{(\mathrm{R}+\mathrm{h})^2}

\begin{aligned} & \mathrm{h}=3200 \mathrm{~km}=\mathrm{R} / 2 \\ & \mathrm{~W}_2=\mathrm{m} \frac{\mathrm{GM}}{\left(\frac{3 \mathrm{R}}{2}\right)^2} \Rightarrow \mathrm{W}_2=\frac{4}{9} \mathrm{mg} \\ & \mathrm{W}_2=\frac{4}{9} \times 18 \Rightarrow \mathrm{W}_2=8 \mathrm{~N} \end{aligned}

 

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Deependra Verma

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