The physics archive contains legacy physics content, and is not being updated with new content. For our most up-to-date, mastery-enabled courses, check out Middle School Physics, High School Physics, …

Physics is built on a foundation of math and it seeks to explain all phenomena in the universe. It forms the basis for other sciences like chemistry and biology. Physics uses simple yet elegant math to …

Let me drop my physics textbook slightly above my desk. Because of gravity the book falls down, right, yet then it’s stopped by the desk. Now the desk exerts a normal force upon the book. Without it – …

Aug 18, 2025 · Explore Khan Academy’s updated AP Physics 1 and NGSS-aligned Middle School Physics courses, featuring new videos, interactive practice, and hands-on activities to support …

Let's solve some problems to better understand the behavior of forces that act on objects, and their effects on motion. In the process, we will clear some common misconceptions.

If you’ve mastered this content and want to explore physics at the next level, we recommend our AP Physics 1 and AP Physics 2 courses. Give us feedback on this course

This course has been deprecated. We recommend exploring our improved High School Physics, AP Physics 1, and AP Physics 2 courses instead.

Let's think about what physics is and what topics are covered in an introductory physics course.

物理学研究的是决定我们身处的物质世界的基本原理。我们将从运动自身开始。然后，我们将在许多不同的实际情况中了解力、动量、能量和其它概念。为了更好地理解物理学，你需要有牢固的代数基础以 …

Learn physics using videos, articles, and NGSS-aligned practice exercises. Explore the fundamentals of motion and forces, non-contact interactions, energy, and waves.