Assertion :In circular motion, dot product of velocity vector (→v) and acceleration (→a) may be positive, negative or zero. Reason: Dot product of angular velocity vector and linear velocity is always zero.
Assertion and reason both are correct as angular velocity is always orthogonal to the linear velocity in circular motion. However, acceleration has two components, a linear component and a radial component. But, reason is a stand alone statement and gives no clarity on acceleration of the object. Hence, option B.