A body is taken to a height of $nR$ from the surface of the earth. The ratio of the acceleration due to gravity on the surface to that at the altitude is

At what height from the ground will be the value of $g$ be the same as

that in $10 km$ deep mine below the surface of earth.

Gravity meters measures in units of mGal where 1 Gal (or 1 galileo) is the C.G.S unit of acceleration due to gravity. A gravity meter shows a reading of +300 mGal at a place where the normal 'g' is 9.78 $m s^{-2}$. The correct 'g' at that place where the reading was taken is _____ $m s^{-2}$.

The gravitational potential difference between the surface of a planet and a point $20\ m$ above it is $16\ J/kg$. Then calculate the work done in moving a $4\ kg$ mass by $8\ m$ on a slope $60$ degree from the horizontal, is:

বিষুবীয় অঞ্চল থেকে মেরু অঞ্চলের দিকে অভিকর্ষীয় ত্বরণ-