Which of the following statements are true about acceleration due to gravity?

Options

A. `g` decreases in moving away from the centre if `r gt R`.
B. `g` decreases in moving away from the centre if `r lt R`
C. `g` is zero at the centre of earth
D. `g` decreases if earth stops rotating on its axis.

Answer

A, C

Explanation

If `rgtR, g'=gR^(2)/((R+h)^(2))=g(R^(2))/(r^(2))`
If `rltR, g'=g[(R-d)/R]`
where `d` is the depth below the surface of earth.
If `d=R, g=0`
Further, due to rotation `g'=g-Romega^(2)cos^(2)theta`
If `omeaga=0`, then `g` increases.