# Homework Help: Find acceleration vector of a car travelling on a circular path

1. Oct 17, 2012

### Phys121VIU

1. The problem statement, all variables and given/known data
A car is travelling eastward turns north by travelling in a circular path at uniform speed as shown in the picture. the length of arc ABC is 235m and the car completes the turn in 36.0s

a) Find the acceleration vector of the car when it is at B. Express answer in terms of unit vectors$\hat{i}$ and $\hat{j}$

2. Relevant equations
arad = V2 / r = 149.6m

circumference of a circle = 2nr

3. The attempt at a solution

Because the car is travelling at uniform speed, there is no tangential acceleration conponent, just radial acceleration. From there I found the radius of the arc the car is travelling on

r = [(235) x 2] / ∏

So radial acceleration = [V2] / r

but velocity isnt given..so there are two unknowns and therefore i cant solve for arad, therefore i am stuck.. any hints would be appreciated!

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• ###### Photo 2012-10-16 10 27 06 PM.jpg
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2. Oct 17, 2012

### mishek

Can you work out something with bolded text?

3. Oct 17, 2012

### Phys121VIU

I see, its travelling at constant velocity so it is the same all along the arc.

velocity = d / t

= 235m / 36.0s

= 6.53m/s

and with that, the radial acceleration can be found :

= (6.53m/s)2 / 149.6m

= 0.285 m/s2 = 0.285 m/s2 $\hat{i}$

Thank you!
EDIT***

b) Find the velocity vector at B. Express answer in terms of $\hat{i}$ and $\hat{j}$

This is part two..i just want to see if im on the right track..

Is the velocity at B = (6.53m/s) $\hat{j}$ ??

(I didnt think these questions would be this simple..):S

Last edited: Oct 17, 2012