Question

At what height above surface of earth the weight of an object will become 1\4 times of the weight at earth surface?( Radius of earth=6400km)

Answer 1

For this question,
We have the formula, g' = g/(1+h/R)^2
Here g' = acceleration due to gravity at the height
g = 9.8m/s^2
R = radius of earth
h = height
g/g' = (1+h/R)^2
4 = (1+h/R )^2
1+h/R = 2
h/R = 1
h = R
So at the height of 6400 km the value of g is 1/4 th of its original value .