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] $
