Angular acceleration

Definition

Angular acceleration is the rate of change of angular velocity over time. It describes how quickly an object is rotating or spinning.

5 Must Know Facts For Your Next Test

1. Angular acceleration is usually denoted by the Greek letter $\alpha$.
2. The unit for angular acceleration in the SI system is radians per second squared ($\text{rad/s}^2$).
3. Angular acceleration can be calculated using $\alpha = \frac{d\omega}{dt}$, where $\omega$ is angular velocity and $t$ is time.
4. A positive angular acceleration indicates an increase in rotational speed, while a negative value indicates a decrease.
5. In fixed-axis rotation, angular acceleration is directly proportional to the net torque applied to an object.

Review Questions

• What symbol is commonly used to represent angular acceleration?
• How do you calculate angular acceleration if you know the initial and final angular velocities and the time interval?
• What does a negative value for angular acceleration indicate?

Related terms

Angular Velocity:

The rate at which an object rotates or spins around an axis; measured in radians per second ($\text{rad/s}$).

Torque:

A measure of the force that causes an object to rotate about an axis; calculated as the product of force and lever arm distance.

Moment of Inertia:

A scalar quantity representing an object's resistance to rotational motion about a specific axis; depends on mass distribution.