What is the Angular Velocity of a Point Moving in a Circular Path?

[Sheen91]

Homework Statement

[PLAIN]http://img707.imageshack.us/img707/2066/question3.jpg

Homework Equations

v = r' $$\hat{r}$$ + r*θ' (^θ)

The Attempt at a Solution

I was sure I knew how to do this question but made a mistake somewhere, because my answer is not right. So here is my working out.

l r' l = 11mm/s
Θ' = ?
r = 78mm

Looking at the question above.

[PLAIN]http://img20.imageshack.us/img20/8729/lolbo.jpg

 

[ehild]

The angular velocity is usually given in radian/s. Check the answer in your book. Otherwise your result looks OK.

ehild

 

[Sheen91]

There are two answer rads/s and degs/s, both are not the same as my answer.

I definitely did something wrong.

 

[ehild]

The sign can be wrong. The velocity shown makes the angle θ smaller.

ehild