# Speed, Average Acceleration, and Velocity

1. Sep 4, 2009

### slu1986

1. At t = 0, an automobile traveling north begins to make a turn. It follows one-quarter of the arc of a circle of radius 9.3 m until, at t = 1.60 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.

2. Relevant equations
average speed = distance traveled/time of trip
change in velocity = vf - vi
average acceleration = Δv/Δt

3. I understand how to calculate the change in velocity and average speed and acceleration, however the problem throws me off b/c of the way it's set up..I am confused at where to begin solving this problem b/c of the radius and the whole arc thing. If someone could please help me get started I would appreciate it. Thanks.

2. Sep 4, 2009

### rl.bhat

In the problem it is said that the car does not change its speed during the turn.
So during turn speed is constant.
The car is moving in a uniform circular motion. So the velocity is always tangential to the circular path. The velocity is a vector. It changes its direction from north to east. Let V1 in the north direction and V2 is in east direction.Their directions are perpendicular to each other. So the change in the velocity is V2 - V1. Their magnitudes are equal. To find the resultant of these vectors, along with V2 draw a vector in the south direction, And then find the resultant.
For the part c, what is the acceleration of the body which is moving in a uniform circular motion?