Basic Concepts
In a nutshell: Forces are pushes or pulls that affect motion, explained by Newton’s Laws.
## What Are Forces?
A **force** is a push or pull. Forces make things move, stop, or change direction. The study of how and why objects move is called **mechanics**.
## Newton’s Laws of Motion
- **First Law (Inertia):** Things want to keep doing what they’re doing—moving objects keep moving, and stopped objects stay stopped—unless a force acts on them.
- **Second Law:** The bigger the force, the more something accelerates: \( F = ma \) (Force = mass × acceleration).
- **Third Law:** For every action, there’s an equal and opposite reaction.
## Everyday Forces
- **Gravity:** Pulls you toward Earth.
- **Friction:** Slows things down when they rub together.
- **Magnetism:** Pulls or pushes objects without touching them.
## Why Forces Matter
Forces explain why we walk, cars drive, and planes fly!
Examples
- A soccer ball moves when you kick it (force applied).
- Friction between your shoes and the floor lets you walk without slipping.
Key terms
- Force
- A push or pull that can cause an object to move, stop, or change direction.
- Friction
- A force that resists motion between two surfaces.
- Gravity
- A force that pulls objects toward one another, like toward the Earth.