If g on the surface of the earth is `9.8 m//s^(2)`, find its value at a height of 6400 km.
(Radius of the earth = 6400 km)

Explanation

Let g at a height h be `g_(h)`
`g_(h) = (g)/((1+(h)/(R))^(2))`
`h = 6400 km, R = 6400 km, g = 9.8 m//s^(2)`
`g_(h) = (9.8)/((1+(6400)/(6400))^(2)) = (9.8)/((1+1)^(2)) = (9.8)/(4) = 2.45 m//s^(2)`