Gravitation Question 27
Question: At what altitude in metre will the acceleration due to gravity be 25% of that at the earth’s surface (Radius of earth = R metre)[ISM Dhanbad 1994]
Options:
A) $ [\frac{1}{4}R] $
B) R
C) $ [\frac{3}{8}R] $
D) $ [\frac{R}{2}] $
Show Answer
Answer:
Correct Answer: B
Solution:
$ [g’=g{{\left( \frac{R}{R+h} \right)}^{2}}] $
Þ $ [\frac{g}{4}=g{{\left( \frac{R}{R+h} \right)}^{2}}] $
Þ $ [\frac{1}{2}=\frac{R}{R+h}] $ Þ$ [R+h=2R] $ \ $ [h=R] $
