Question

What is the angle between velocity vector and acceleration vector in uniform circular motion ?

Answer 1

Hint: In physics, a vector is a quantity with both magnitude and direction. It's usually represented by an arrow with the same direction as the amount and a length proportionate to the magnitude of the quantity. A vector does not have location, even though it has magnitude and direction. A vector is not affected if it is shifted parallel to itself as long as its length is not modified.

Complete answer:
The temporal rate of change of angular velocity is referred to as angular acceleration in physics. There are two forms of angular velocity: spin angular velocity and orbital angular velocity, hence there are two forms of angular acceleration: spin angular acceleration and orbital angular acceleration. The angular acceleration of a rigid body around its centre of rotation is known as spin angular acceleration, while the angular acceleration of a point particle around a fixed origin is known as orbital angular acceleration.
https://commons.wikimedia.org/wiki/File:Centripetal_force_diagram.svg
The velocity of a particle representing uniform circular motion is always perpendicular to the particle's centripetal acceleration. Because the particle's tangential acceleration is zero, the only acceleration that acts towards the centre of the circular route is centripetal acceleration.
As a result, the angle between the particle's velocity and acceleration when describing uniform circular motion is 90 degree.
In a uniform circular motion, velocity is always along the tangential direction, and acceleration is always towards the centre, hence the angle between the velocity and acceleration vectors is always $\dfrac{\pi }{2}$. However, the angle between velocity and acceleration might be sharp or obtuse in general.

Note:
Angular velocity may be divided into two categories. The pace at which a point object circles around a given origin, or the temporal rate at which its angular location changes relative to the origin, is referred to as orbital angular velocity. In contrast to orbital angular velocity, spin angular velocity relates to how quickly a rigid body rotates with regard to its centre of rotation and is independent of the choice of origin.