# ANGULAR VELOCITY-ANGULAR ACCELERATION

 ANGULAR VELOCITY-ANGULAR ACCELERATION DEFINITION Angle traversed by a body in circular motion in unit time is called angular velocity. OR The rate of change of angular position of a body is called angular velocity. Consider a particle “P” moving in a circular path of radius “r”. The angular position P1 is q1 at instant t1 and q2 at instant t2. The angular displacement is q2 – q1 = Dq . Time interval = t2 –t1 =Dt Since the angle traced per sec by a body moving in circle is called its average angular speed denoted by wav. Therefore, wav = Dq / DtUnit for angular velocity is rad /sec OR rev/sec. INSTANTANEOUS ANGULAR VELOCITY The angular velocity at a particular instant is called instantaneous angular velocity. If D t is very small i.e. D t è 0 then Dq / Dt is called instantaneous angular velocity. Unit for angular velocity is rad /sec OR rev/sec. DIRECTION OF ANGULAR VELOCITY Direction of angular velocity is given by right hand rule, which states that if we curl the fingers of right hand in the direction of rotation then thumb will represents the direction of angular velocity. ANGULAR ACCELERATION Rate of change of angular velocity of a body is called angular acceleration. It is denoted by a . If w1 is angular velocity of a body moving in circle at instant t1 and w2 is angular velocity of body at instant t2 then, if Dt is very small then acceleration is called instantaneous angular acceleration. citycollegiate.com UNIT Unit of angular acceleration is rad/sec2. DIRECTION Direction of angular acceleration is same as of w