NEET Class neet Answered

Acceleration due to gravity g = G ( M / R² ) ..................(1)

where G is universal gravitational constant , M is mass of earth and R is radius of earth .

If ρ is density of earth , then mass M = volume × density =   (4/3)πR³ × ρ

Hence eqn.(1) is rewritten as

g = [ (4/3)π G ] R × ρ

From above expression, we see that acceleration due to gravity is directly proportional to radius R and

also directly proportional to density ρ .

Let g' be the acceleration due to gravity of new planet that has size three times of earth.

If earth and new planet has same density , then their ratio of acceleration due to gravities is

( g / g' ) = R/ (3R) = 1/3