## Backlinks

## Table of Contents

## 1 Earth's Gravitatonal Field

Extends infinitely large, but there is a point whereby it is imperceivable.

First, *Newton's Law of Universal Gravitation*.

\(\vec{F_g} = -\frac{M_2 M_1 G}{R^2} \cdot \hat{r}\), where \(G\) is the Universal Gravity Constant and \(r\) is a direction ("unit vector") tha points from \(M_1\) to \(M_2\) (so \(\hat{r} = \frac{\vec{r}}{r}\)).

Often, this is written as…

\(\vec{F_g} = \frac{-G M_1 M_2}{r^3} \vec{r}\). It is \(r^2\), but doing this and multiplying it to \(\vec{r}\) is to resolve the need to rid if the direction.

## 2 Potential Energy

**Whenever we talk about "energy", we are really talking about the CHANGE
in energy.**

Potential Energy Location:

* ... ... ... \infty