3. Angular acceleration If the angular velocity of p is not constant, then the average angular acceleration is defined as △t (8-4) The instantaneous angular acceleration is △Od C m (8-5) △t→>0△t t Its dimensions are inverse time squared (T)and its units might be rad/>2orrev/sIf the angular velocity of P is not constant, then the average angular acceleration is defined as (8-4) The instantaneous angular acceleration is (8-5) 3. Angular acceleration t av   =   dt d t t    =   =  →0 lim Its dimensions are inverse time squared ( ) and its units might be or . −2 T 2 rad /s 2 rev /s