Gravitation Question 25

Question: At what height over the earth’s pole, the free fall acceleration decreases by one percent (assume the radius of earth to be 6400 km)[KCET 1994]

Options:

A) 32 km

B) 80 km

C) 1.253 km

D) 64 km

Show Answer

Answer:

Correct Answer: A

Solution:

$ [g\propto \frac{GM}{r^{2}}] $ $ [g\propto \frac{1}{r^{2}}] $

or $ [r\propto \frac{1}{\sqrt{g}}] $

If g decrease by one percent then r should be increase by $ [\frac{1}{2}%] $ i.e. R=

$ [\frac{1}{2\times 100}\times 6400=32\ km] $



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