Mechanics: Degrees of freedom (extremely simple)

[tomedj]

Homework Statement

A particle slides along a wire which is rotating at a constant angular velocity w. In polar coordinates the equation of constraint is :

theta' - w = 0 OR theta - wt = 0. *

What is the equation of constraint in cartesian coordinates?

Homework Equations

The Attempt at a Solution

Is it:

wx - y' = 0 * ?

*all primes are derivatives wrt t.

Thanks in advance, I know it's basic but I've hit a wall and have been looking at it for way longer than is healthy...

 

[cepheid]

Can't you just do a coordinate transformation from polar to cartesian? How is theta defined in terms of x and y?

 

[tomedj]

Can't you just do a coordinate transformation from polar to cartesian? How is theta defined in terms of x and y?

sin(theta) = y/r and cos(theta) = x/r etc.

It's not that simple is it? I could cos or sin both sides of theta = wt but the I'll get something that looks like:

y/r = sin(wt)...