Physics / core

Work-Energy Theorem

Also known as: work-kinetic energy theorem

principle

The net work done on an object equals the change in its kinetic energy — the bridge between force and motion. Often much easier to solve motion problems using energy methods rather than tracking forces.

💡 Intuition

The total work done on an object is exactly what changes its kinetic energy.

Core Idea

This theorem bridges force-based thinking (work) with energy-based thinking (kinetic energy).

🔬 Example

Push a cart (do positive work) → it speeds up (gains KE). Friction (negative work) → it slows down (loses KE).

🎯 Why It Matters

Often much easier to solve motion problems using energy methods rather than tracking forces.

⚠️ Common Confusion

Only net work changes KE—individual forces may do positive or negative work.

Related Concepts

Prerequisites

Next Steps

How Work-Energy Theorem Connects to Other Ideas

To understand work-energy theorem, you should first be comfortable with work and kinetic energy. Once you have a solid grasp of work-energy theorem, you can move on to power.

Go Deeper

Frequently Asked Questions

What is Work-Energy Theorem in Physics?

The net work done on an object equals the change in its kinetic energy — the bridge between force and motion.

Why is Work-Energy Theorem important?

Often much easier to solve motion problems using energy methods rather than tracking forces.

What do students usually get wrong about Work-Energy Theorem?

Only net work changes KE—individual forces may do positive or negative work.

What should I learn before Work-Energy Theorem?

Before studying Work-Energy Theorem, you should understand: work, kinetic energy.

🧪 Visualization Static

Visual demonstration of this concept.