Torque and angular momentum

This course is a part of AP®︎ Physics 1, a 12-course Topic series from Khan Academy.

Everything we've learned about motion, forces, energy, and momentum can be reused with a few tweaks to analyze rotating objects. In this lesson, you'll learn about rotational motion, rotational inertia, torque, and angular momentum.

This course contains 8 segments:

Introduction to rotational motion

Learn what angular displacement, angular velocity, and angular acceleration mean, as well as how they relate to their linear counterparts.

Angular kinematics

Learn the relationships between angular displacement, angular velocity, and angular acceleration using the rotational kinematic formulas.

Torque and equilibrium

Anyone who has ever opened a door has an intuitive understanding of torque. In this lesson, we'll explore why and how objects rotate using the concepts of torque and rotational equilibrium.

Rotational inertia and angular second law

In this lesson, we'll learn how the distribution of mass can impact how easily the angular velocity can be changed around an axis. This property is called rotational inertia.

Rotational kinetic energy

Does a baseball have more kinetic energy if it is spinning? In this lesson, we'll learn how to determine the rotational kinetic energy of an object so we can figure out how much more energy the baseball has.

Angular momentum and angular impulse

In this lesson, we'll learn about angular momentum and angular impulse, and how these quantities are related to translational (or linear) momentum.

Conservation of angular momentum

Angular momentum is constant where there is no net torque, just like how linear momentum is constant when there is no net force. In this lesson, we'll learn about the conservation of angular momentum and how to apply the new conservation law to solve problems.

Gravitational potential energy at large distances

Until this lesson, we have always assumed the gravitational field is uniform and potential energy is equal to mgh. Now we'll learn how to find the gravitational potential energy at large distances when these assumptions no longer hold.