# What is the circumference of the track?

1. Dec 21, 2009

### Brittykitty

A student runs at a speed of 8.50 m/s on a circular track. If she accelerates a 1.03 m/s2, what is the circumference of the track?

8.5m/s*1.03m/s?

2. Dec 21, 2009

### AEM

Re: Circumfrerence

The wording of the problem implies that the velocity of the girl is a constant and therefore the acceleration referred to is centripetal acceleration. There is a nice equation that expresses the relationship between radial acceleration (centripetal acceleration), velocity and the radius for motion in a circle. So all you need to do is use that to find the radius and use $C = 2 \pi r$ to compute the radius.

Last edited: Dec 21, 2009
3. Dec 21, 2009

### Brittykitty

Re: Circumfrerence

Thanks! :) so it would be:

2(3.142)14?

4. Dec 21, 2009

### AEM

Re: Circumfrerence

No, I don't get that at all. The equation I have in mind is $a = \frac{v^2}{r}$. That will allow you to calculate r.

Last edited: Dec 21, 2009
5. Dec 21, 2009

### AEM

Re: Circumfrerence

That's a v squared. It doesn't come out on my computer screen.