**ANGULAR ACCELERATION**

**What is Angular Acceleration, Centripetal Acceleration and Tangential Acceleration?**

Angular Acceleration is the rate of change of angular velocity. It is usually expressed in and is denoted by a Greek letter α (alpha). It is also a vector quantity.

**Note** : **1.** If the body is moving along a circular path of radius r and with angular acceleration α, then its linear acceleration is given by

**a = αxr**

**2.** When a body moves along a circular path, its linear acceleration will have two components; one is the normal component and other is tangentia1 component. The normal component of the acceleration is known as normal or centripetal acceleration (ac). Its value is given by

**3.** When the body moves along a circular path with uniform velocity, then there will be no tangential acceleration, but it will have only centripetal acceleration.

**4.** When the body moves along a straight path, then there will be no centripetal acceleration, but it will have only tangential acceleration, in the same direction as its velocity and displacement.