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.

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

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

In the physics sense, you are doing no work on the book. However, even if you don't have a book in your hand, if you twist side to side, your muscles get warm and you release energy.

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

¡Bienvenido a las Lecciones de física! La física es el estudio de la materia, el movimiento, la energía y la fuerza. Aquí puedes explorar videos, artículos y ejercicios por tema. Mantenemos estas lecciones …