Where does the center of gravity of the atmosphere of the earth lie? `(AS_(2))`

Where does the centre of gravity of a sphere and triangular lamina lie?

Explain some situations where the center of gravity of man lies outside the body. (AS_(1))

The height at which the acceleration due to gravity becomes (g)/(9) (where g = the acceleration due to gravity on the surface of the Earth) in terms of R, the radius of the Earth, is:

If the acceleration due to gravity on the surface of the Earth is 9.8m//s^(2) , what will be the aceleration due to gravity on the surface of the planet whose mass and radius both are two times the corresponding quantities for the Earth.