Question

Suppose a planet exist whose mass and radius both are half that of the earth. The acceleration due to gravity on the surface of this planet will be double? Justify.

Answer 1

For earth, g = GM/R^2
For the other planet,
m = M/2
r = R/2
g' = GM/r^2 = G(M/2)/(R/2)^2
g' = 2 GM/R^2
g' = 2g
Thus the acceleration due to gravity on that planet will be twice of earth; that means 19.6 m/s^2

Answer 2

BECAUSE THE FORMULA OF ACCELERATION DUE TO GRAVITY = 1/R SQUARE
SO IT IS INVERSLY PROPORTIONAL
THEREFOR IF RADIUS REDUCED THAN G INCRESES