# Independent variable.

## Homework Statement

Hi there,

I'm doing a practical investigation to see how the centripetal force required for circular motion varies with the frequency of rotation, and I was just wondering which is the independent variable, and which is the dependent one.

The investigation involves various weights tied to a string that's threaded through a tube and tied to a rubber stopper at the other end. The rubber stopper is spun around horizontally and the frequency at different masses is measured.

I'll be keeping the radius and mass of the stopper constant.

## Homework Equations

F=4 m r pi^2 f^2

## The Attempt at a Solution

I think that the frequency is the dependent variable because it is affected by different magnitudes of centripetal force, but at the same time the frequency affects the force required for circular motion. So I'm not sure which is dependent and independent (It's just for my graph).

anyone?

Hello Stroodle. You have an interesting experimental design there.
For your design, the different masses are the indepedent variable and the frequency is the dependent variable (however, you may want to plot gravitational force of the masses as a function of the frequency even though frequency is dependent). As you have already indicated, you will find a parabolic relationship between the two. Good luck on your lab.

-PL

Thanks for that Inutard. I really appreciate your help.