Question

Compare the gravitational force of attraction on a 1.0kg object when it is at the surface of the moon to the gravitational force on the same object when it is at the surface of earth.(mass of the moon =7.35 X10^22kg,radius of the moon = 1.78x10^6m,mass off earth = 6x10^24;radius of earth 6.4x10^6m)

Answer 1

gravitational force:

$F=\frac{GMm}{R^2}$

for moon:

$F_1=\frac{6.67\cdot10^{-11}\cdot7.35\cdot10^{22}}{(1.78\cdot10^6)^2}=1.55$ N

for earth:

$F_2=\frac{6.67\cdot10^{-11}\cdot6\cdot10^{24}}{(6.4\cdot10^6)^2}=9.77$ N

$F_2/F_1=9.77/1.55=6.3$