How Does Changing the Radius Affect Centripetal Force in a Lab Experiment?

[whitesound]

Centripital Force Lab - PLEASE HELP!

Homework Statement

Ok so i need to do this lab, write a report, and prepare a defence for tomorrow

pretty much i spin a mass horizontally on a string attached vertically to a force sensor. i hold onto a plastic tube through which the string goes and using the force sensor i get data (a force time graph) from which i can get the average force and the period/frequency

for my part i need to use different radii of the string and graph a relationship between the force and the radius length

so i did all of this but I am really confused by my results:
if i spin the mass fast the period is small and the force is large
if i spin the mass slowly (fast enough to keep the mass horizontal) i get a larger period and a smaller average force

but changing the radius of the string does not seem to change much (anything)

so my question to you is how does the radius relate to everything if other things are kept constant (or as constant as possible)

so i really need some help, any hints or something that would help me get the answer.

btw i do know the mass of the rubber stopper (mass on the end of the string) = 12.4 grams

any help is greatly appreciated !

Homework Equations

The Attempt at a Solution

 

[whitesound]

well no one replied ... but that's ok because I am pretty sure that I've figured it out:
since i have a force sensor all i need to do is make sure to keep the period as constant as possible and then i will see a relationship between changing Fc and radius

 

[whitesound]

oh and i realize now that i really didn't give much informations about the experiment but i thought most would know it since it one of the most common centripetal force labs

also i tried to post a link to the lab outline but due to forum restrictions that wasn't possible