Q) A body weighs 72N on the surface of the earth, What is the gravitational force due to earth at a height equal to half the radius of the earth from the surface?

LET MASS OF THE BODY BE m

THEREFORE F=GMm/r²

FORCE AT SURFACE OF EARTH = (3R/2)²

FORCE AT DISTANCE R/2 FROM SURFACE R²

^{= FORCE AT DISTANCE R/2 FROM SURFACE = 4/9 FORCE AT SURFACE OF EARTH}

^{= FORCE AT DISTANCE R/2 FROM SURFACE=32 N}