Question

The mass of the moon is $1$% of mass of the earth. The ratio of gravitational pull of earth on moon to that of moon on earth will be:

• A. $1:1$
• B. $1:10$
• C. $1:100$
• D. $1:50$

Answer 1

The correct option is A $1:1$

Mass of moon $=M_m$

Mass of earth $=M_e$

$M_m=\frac{M_e}{100}$

$\therefore F_{M_e}=\frac{G{M}_m{M}_e}{R^2}=\frac{G{M_e}^2}{100R^2}$

and, $F_{M_m}=\frac{G{M}_m{M}_e}{R^2}=\frac{G{M_e}^2}{100R^2}$

$\therefore \frac{F_{M_e}}{F_{M_m}}=\frac{1}{1}$