28-Sept, 2016 . Lab #8: Demonstration - Centripetal Acceleration vs. Angular Frequency

 Lab #8: Demonstration - Centripetal Acceleration vs. Angular Frequency

Dahlia - Ariel - Carlos

28-Sept-2016

The purpose of the lab#8 is to help student know how to determine the relationship between centripetal acceleration and angular speed.
I. Set up:

- There was a huge disk which was connected with a motor, thus, we could control the speed of rotation of the disk. 

- At the center of this disk, there was a force sensor which was connecting the center of the disk and an object through a string. This sensor provided value of the centripetal force.

- At the edge of the disk, there was a sensor which read the value of liner velocity of the disk.

- All of sensors were connected with log pro, thus, we could read value of linear velocity and centripetal force.

- First, we let the disk rotate with a certain value of velocity and object mass, but the radius (the length of the string) was changed.
- Second, We let the disk rotate with a certain value of object mass and radius, but we changed value of the speed.
- Finally, we let the disk rotate with a certain value of radius and speed, but we changed value of the mass of object.

By using log pro, I could read value of linear velocity and centripetal force.

II. Collected and analyzed data:

This picture was collected data from 9 trials.

First 4 was varied radius, and next was varied speed, finally was varied the mass of object.

From Free Body Diagram, I had formula of the centripetal force. To check this formula, I graphed this formula with data I collected from the experiment.  

First, I entered data to a sheet of Excel

Then, I graphed them

in graph "F vs. m", the slope would be rw^2 = 0.0409

in graph "F vs. R", the slope would be mw^2 = 3.6547

in graph "F vs. omega", the slope would be rm = 1.1894

To make them become more specific, I graph them one more time

in graph "F vs. mr", the slope would be w^2 = 7.4

in graph "F vs. r*omega", the slope would be m = 1.60

in graph "F vs. m*omega", the slope would be r= 1.08

III. Conclusion:

From collected data with influenced from graph, I could conclude that F=mrw^2 was true.
when I kept the same value of speed and radius, if I decreased mass by half, the value of centripetal force also decreased by half.