a particle is describing uniform circular motion in the anti clockwise sense such that its time period of revolution is T. at t=0 the particle is observed to be at A. if B1 be the angle between acceleration at t= T/4 and average velocity in the time interval 0 - T/4 and B2 be the angle b/w acceleration at t= T/4and the change in velocity in the time interval 0-T/4, then the value of B1 and B2 are?

your question seems wrong... B1 for T/4 and B2 also for T/4..?

no B1 is the angle b/w acceleration and average velocity but B2 is the angle b/w acceleration and change in velocity

Your question really seems wrong. B2 is the angle between acceleration and change in velocity what do you mean by change in velocity. Change in velocity is called acceleration. So according to you B2 will be the angle at time T/4 between acceleration and acceleration. Correct your question.

its correct nd in this ques by change in velocity they mean velocity at t=T/4 - velocity at t=0... thats how i interpreted it.......nd RATE OF change in velocity is called acceleration

here Vavg = displacement/time ... as time is a scalar and others are vectors.. their direction is same... now displacement and acceleration make an angle of 135 degrees..... (by using angle between vectors..) now change in velocity is V2-V1 ... here V2 & V1 have same magnitude but r perpendicular... hence V2-V1 makes 45 degrees with V2 , which is perpendicular to acc. hence angle b/w V2-V1 & acc. is 45 degrees