This document provides an introduction to the language of physics. It discusses how mathematical equations are used to describe physical phenomena and symbols commonly used in equations. Examples are provided on how to interpret equations and use dimensional analysis to check if equations are dimensionally consistent by evaluating the dimensions on each side. Students are assigned textbook problems evaluating physics expressions using these concepts.

1. Unit 1: Intro to Physics
Lesson 3: The Language of Physics

2. Objectives
The student will be able to:
• Interpret data in tables and graphs, and recognize
equations that summarize data
• Use dimensional analysis to check the validity of
expressions

3. The Language of Physics
• Mathematical equations are used to describe physical
phenomenon
• Learning to read a mathematical formula is like learning a
new language
• For example:
Equation Simple English
ΣF = ma
A net force is the result of some mass
undergoing an acceleration.

4. Common Symbols
Symbol Meaning
Δ difference, change in
Σ sum, total
g acceleration due to gravity
x displacement

5. Textbook Shorthand Note
• Any symbol written in standard font is to be considered a
unit
• Any symbol written in italic font is considered to be a
variable

6. Evaluating Physics Expressions
• Dimensional Analysis: the process of evaluating dimensions
in an equation to determine its validity
• Rules of Dimensional Analysis
• Quantities can only be added or subtracted if they have
the same dimensions
• The two sides of any given equation must have the same
dimensions
• Any unit can be multiplied or divided by another unit

7. Dimensional Analysis Example 1
• Determine whether or not the following equation is
dimensionally consistent.
• Where v is measured in meters/second, x is measured in
meters, and t is measured in seconds.
𝑣 =
𝑥
𝑡

8. • Determine whether or not the following equation is
dimensionally consistent.
• Where x is measured in meters, t is measured in seconds,
and a is measured in meters per second squared.
• Solve the above equation for a, and determine whether or
not your new equation is dimensionally consistent.
Dimensional Analysis Example 2
Δ𝑥 =
1
2
𝑎 ⋅ 𝑡2

9. Think/Pair/Share
p.25 #1-3

10. Homework
p.29 #23, 27, 28