# Uniform circular motion proportionalities

1. Apr 4, 2005

### MiniTank

I have a lab with which I am having some major difficulties.

(a) Whats the relationship between frequency of revolution and
- the magnitude of the force causing the circular motion(centripetal force)?
- the radius of the circular path?
- the mass of the object?
(c) Find the proportionalities between frequency of revolution and the variables in (a)
(d) cominge the three results from (c) to obtain the equation for frequency in terms of the tension, the radius, and the mass. check your equation using your data points
(e) The following relationship gives the magnitude of the net force causing the acceleration of an object in uniform circular motion:
$$\SigmaF = 4\pi^2mrf^2$$
Rearrange this equation to isolate the frequency. Compare this result with the equation you derived in (d). Indicate the likely causes for any discrepancies.
(f) Draw a FBD for the rubber stopper***
(g) Explain how this investigation illustrates all three of Newton's laws of motion.

***the rubber stopper is attatched to a string which goes through a hollow tube which is attached to weight .. you twirl the stopper from the tube

Heres what I know
(a) the frequency and radius have an inverse relationship
.. the other variables im not sure
(b) i know what the graph looks like for radius:
|
|
|
\_________
.. something like that
(c) same as above
(d) I need help with
(e) I can rearrange the equation to:
$$f=\sqrt{\frac{\SigmaF}{4\pi^2mr}}$$
the next part is hard to do without (d)
(f) I think it has a Tension force going to the left or right, and a Force of gravity, not sure.
(g) Could maybe figure this out after knowing the other answers.

If you need my results just ask, but I doubt you do.

Thanks

BTW i know its alot but any help would be appreciated.

2. Apr 4, 2005

### MiniTank

could someone delete this thread .. i accidentally pressed post instead of preview.. thanks

3. Apr 4, 2005

### whozum

Delete it yourself by clicking edit and selecting the first options.

4. Apr 4, 2005

### MiniTank

i wanna delete the whole thread, not just the post... b/c it is a re-post .. the proper one has the same title .. you cant delete threads