# Changing position in circular motion

1. Jun 20, 2007

### alik

Could you help me with question : How does the x and y component of the position change in circular motion?

2. Jun 20, 2007

### cristo

Staff Emeritus
Draw a circle at the origin of x and y axes. Then, as you move your pen around the circle, the x and y components of the position of your pen will change.

Your question isn't very precise-- what do you mean by "how"? Are you looking for equations here? Is this a homework question? If so, then state the exact question, and your attempt before we can help you.

3. Jun 20, 2007

### alik

;) it's my exam's question on monday . It's the exact formulation of these question and I think it's about the relation between x y components and the angle - yes any equation

4. Jun 20, 2007

### nrqed

Do you mean "change with time"? Do you mean *uniform* circular motion?

In any case, have you seen the formula $\theta(t) = \theta_i + \omega t$ for circular motion at constant speed? If yes, the answer is simple. If not, I am not sure what they are looking for in terms of an answer. If you fix the time, it's pretty clear how to write x and y at a given time in terms of the angle at that same time $\theta(t)$ and the radius R of teh circle.