# Distance of travel in circular motion?

1. May 16, 2012

### CommandoDude

I'm trying to figure out the distance traveled in a circular motion. This is for a traffic court case, I need to figure out how far my car traveled in an intersection.

So far, I've only been able to find equations for determining speed. I have speed. I have time. I also have the radius of the circular movement (I measured the intersection and made an average to determine the curve because the turn was not a perfect circle). What I need is distance.

What would be the equation to determine the distance traveled?

2. May 16, 2012

### mesa

Not being a perfect circle messes this up a bit but if it's not too far out the circumfrence of a circle is 2∏r with r being your radius. If i'ts a 90 degree turn then your distance would be ≈ 2∏r/4 or ∏r/2 for your distance. A 180 degree turn would be twice that.

3. May 16, 2012

### davenn

Hi there
welcome to PF :)

since its something that actually happened.
what is stopping from physically measuring that distance ?
through an intersection so it must be in the 10 - maybe 100metres max
that is easily measurable with a good tape measure etc
you, I assume are not talking about half a km (500m) ?

cheers
Dave

4. May 17, 2012

### davenn

are you ok are you a parrot??

why repost most of my post ??
thats a very pointless thing to do

to the Mods
I was considering reporting his post but it didnt fall within the guidelines

DAve

5. May 17, 2012

### Whovian

Also, if you have distance and time, you could use that, with $\displaystyle\bar{\left|\vec{v}\right|}= \dfrac{\left| \vec{p}\right|}{t}$, where p is the distance travelled.