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An object is taken to a height above the surface of earth at a distance \frac{5}{4} \mathrm{R} from the centre of the earth. Where radius of earth, \mathrm{R=6400 \mathrm{~km}}. The percentage decrease in the weight of the object will be :

Option: 1

36%


Option: 2

50%


Option: 3

64%


Option: 4

25%


Answers (1)

best_answer

\mathrm{R+h=\frac{5}{4}R}(from the centre of earth)

\mathrm{h=\frac{R}{4}}

\mathrm{\frac{g_n}{g}=\frac{R^2}{(R+h)^2}=\frac{16 R^2}{25 R^2} }

\mathrm{g_n=\frac{16}{25} g}

Weight on the eanth surface \mathrm{= mg }

Weight of the object at height \mathrm{h=m g_n}

\mathrm{\frac{w}{w_n} =\frac{m g}{m g_n}=\frac{25}{16} }

\mathrm{ \frac{w-w_n}{W}=\frac{9}{25} }

\mathrm{\frac{\Delta W}{W} =36%}
The percentage decrease in the weight of the object will be 36%

Hence (1) is correct option.


 

Posted by

Ajit Kumar Dubey

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