We learned about linear momentum and impulse and the law of conservation of momentum in previous lessons.

Now that we've learned about rotational motion, let's introduce angular momentum. This is the momentum of an object or system due to its rotational motion, instead of its translational or linear motion. The equation for angular momentum is very similar to the equation for linear momentum, we just use the rotational inertia instead of mass and angular speed instead of linear speed.

It's important to note that linear momentum and angular momentum are two separate things, and each one is conserved separately. This is different than the law of conservation of energy, where translational and rotational kinetic energy can be converted between each other.

There's also a rotational version of impulse, although we don't have a new word for it (we could call it "angular impulse"). Just like a net external linear force changes a system's linear momentum, a net external torque will change a system's angular momentum.

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Angular momentum

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We learned about linear momentum and impulse and the law of conservation of momentum in previous lessons.

Now that we've learned about rotational motion, let's introduce angular momentum. This is the momentum of an object or system due to its rotational motion, instead of its translational or linear motion. The equation for angular momentum is very similar to the equation for linear momentum, we just use the rotational inertia instead of mass and angular speed instead of linear speed.

It's important to note that linear momentum and angular momentum are two separate things, and each one is conserved separately. This is different than the law of conservation of energy, where translational and rotational kinetic energy can be converted between each other.

There's also a rotational version of impulse, although we don't have a new word for it (we could call it "angular impulse"). Just like a net external linear force changes a system's linear momentum, a net external torque will change a system's angular momentum.