# Question #b9da1

May 18, 2016

Magnitude of gravity $g$ depends on
1. Gravitational constant
2. Mass of earth

#### Explanation:

The word gravity $g$ is is used to denote the acceleration due to gravitational force of attraction of earth.

As per Law of Universal Gravitation the force of attraction between earth of mass ${M}_{e}$, Radius ${R}_{e}$ and an object of mass $m$ placed at the surface of earth is given by the following expression
$F = G \frac{{M}_{e} . m}{R} _ {e}^{2}$

Where $G$ is Universal gravitational constant and has a value $6.67408 \times {10}^{-} 11 {m}^{3} k {g}^{-} 1 {s}^{-} 2$.

Comparing above equation with The equation between force, mass and acceleration given by Newton's Second Law of Motion, considering the scalar part of vectors

$| \vec{F} | = m \cdot | \vec{a} |$, we obtain
$g = G \frac{{M}_{e}}{R} _ {e}^{2}$
We see that magnitude of gravity $g$ depends on
1. Gravitational constant
2. Mass of earth