At t = 0, an automobile traveling north begins to make a turn. It follows one-quarter of the arc of a circle of radius 10.1 m until, at t = 1.52 s, it is traveling east. The car does not alter its speed during the turn.

Question

At t = 0, an automobile traveling north begins to make a turn. It follows one-quarter of the arc of a circle of radius 10.1 m until, at t = 1.52 s, it is traveling east. The car does not alter its speed during the turn.
(a) Find the car's speed.

(b) Find the change in its velocity during the turn.

(c) Find its average acceleration during the turn.

I already determined the speed for (a) to be 10.4 m/s.
I don't understand how to find the change in velocity (b). The equation in the book is v=wt. This didn't work so I would appreciate it if someone could help me understand this conceptually! Thanks!