Mechanics: Degrees of freedom (extremely simple)

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SUMMARY

The discussion centers on deriving the equation of constraint for a particle sliding along a wire rotating at a constant angular velocity (ω) in polar coordinates. The initial equation provided is θ' - ω = 0, leading to θ - ωt = 0. The participant attempts to convert this to Cartesian coordinates, proposing wx - y' = 0 as a potential solution. The conversation emphasizes the complexity of transforming polar coordinates to Cartesian, particularly in defining θ in terms of x and y using trigonometric relationships.

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  • Understanding of polar and Cartesian coordinate systems
  • Familiarity with angular velocity and its implications in motion
  • Basic knowledge of calculus, specifically derivatives
  • Proficiency in trigonometric functions and their applications
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  • Study coordinate transformations between polar and Cartesian systems
  • Learn about angular motion and its mathematical representations
  • Explore the application of derivatives in physics problems
  • Investigate trigonometric identities and their use in coordinate transformations
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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...
 
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Can't you just do a coordinate transformation from polar to cartesian? How is theta defined in terms of x and y?
 
cepheid said:
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)...
 

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