Welcome to Physics

Start here — what physics really is, why it matters, and how to read this guide.

Why this guide exists

Most people leave school thinking physics is a wall of formulas. It isn’t. Physics is just the rules the universe runs on — and once you see why a rule works, the math becomes the easy part.

This guide is written for the person who sat in class thinking, “Wait, but why?” and never got a real answer. I’m going to explain things the way a mechanical engineer thinks about them: with pictures in your head, real objects you can touch, and zero shame in slowing down.

How to read this guide

1. Read in order

   Each page builds on the one before it. Don’t skip ahead — the “aha” moments are stacked.

2. Picture it first, math second

   Every concept starts with a real-world picture. If you can’t see it in your head, the formula won’t stick.

3. Do the thought experiments

   When I say “imagine pushing a shopping cart,” actually pause and imagine it. That’s where understanding lives.

What you’ll learn

What is physics?

The big idea, in plain English.

Motion

Speed, velocity, and acceleration — and why they’re not the same thing.

Forces & Newton's Laws

Why things move, stop, and push back.

Energy & Work

The currency of the universe.

Momentum

Why a slow truck hurts more than a fast bicycle.

Gravity

The force you’ve been feeling your whole life.

Pressure & Fluids

Why ships float and straws work.

Heat & Temperature

What “hot” actually means.

Waves & Sound

How information travels without anything really moving.

Electricity & Magnetism

The invisible force that runs your phone.

Problem-Solving Toolkit

How an engineer actually attacks a physics problem.

You don’t need to be “good at math.” If you can split a bill and read a ruler, you can do everything in this guide.