Question

Find the value of g at a height of 100km from the surface of the earth (radius of the earth =6400 km,on the surface of the earth =9.8ms-2

Answer 1

gupta varies as

g'=g/(1+h/r)^2

But if ,h <<r then

g'=g (1-2h/r) by binomial expansion

Now put values and get answer