Question

At what height over the earth's pole, the free fall acceleration decreases by $1$. (Assume the radius of earth to be $6400 km$)

• A. 1.253 km
• B. 64 km
• C. 32 km
• D. 80 km

Answer 1

Answer: (C)

32 km

Answer 2

$g' = g( 1- \frac{2h}{R})$ i.e. $\frac{g'}{g} = 1 - \frac{2h}{R}$ i.e. $\frac{99}{100}= 1 - \frac{2h}{6400}$ i.e. $h = \frac{3200}{100}$ = 32 km