Angular acceleration

Definition

Angular acceleration is the rate of change of angular velocity with respect to time. It is a vector quantity, often measured in radians per second squared ($\text{rad/s}^2$).

5 Must Know Facts For Your Next Test

1. Angular acceleration is denoted by the symbol $\alpha$.
2. It can be positive (speeding up) or negative (slowing down), indicating the direction of the change in angular velocity.
3. The formula for angular acceleration is $\alpha = \frac{d\omega}{dt}$, where $\omega$ is angular velocity and $t$ is time.
4. Newton's Second Law for rotation states that $\tau = I \alpha$, where $\tau$ is torque and $I$ is moment of inertia.
5. Uniform circular motion has zero angular acceleration because the angular velocity remains constant.

Review Questions

• What does a positive angular acceleration indicate about an object's rotational motion?
• How do you calculate angular acceleration from changes in angular velocity over time?
• Explain how Newton's Second Law for rotation relates torque, moment of inertia, and angular acceleration.

Related terms

Angular Velocity:

The rate at which an object rotates or revolves around a central point, measured in radians per second ($\text{rad/s}$).

Torque:

A measure of the force that can cause an object to rotate about an axis. Torque is calculated as the product of force and distance from the pivot point.

Moment of Inertia:

A scalar value that measures how much torque is needed for a desired angular acceleration about a rotational axis. It depends on the mass distribution relative to the axis.