03-Oct, 2016 . Lab #9: Centripetal Force with a Motor

 Lab #9: Centripetal Force with a Motor

Dahlia - Ariel - Carlos

03-Oct-2016

A apparatus was a system in which when a motor spin at a higher angular speed, a mass revolved around the central shaft at a larger radius and the angle increased. The purpose of lab #9 was to come up with a relationship between angle and angular speed. Moreover, the general way to calculate angular speed was based on period; thus, when doing this experiment, I also measured period of motion. Then, I compared the angular velocity based on angle and angular velocity based on period.
I. Set up:

A apparatus:

- An electric motor mounted on a surveying tripod

- A long shaft going vertically up from the shaft

- A horizontal rod mounted on the vertical rod

- A long string tied to the end of the horizontal rod

- A rubber stopper at the end of the string

- A ring stand with a horizontal piece of paper or tape sticking out.

When doing this experiment, 

- I got h by putting a horizontal piece of paper tape on a ring stand and slowing raising the piece of paper until the stopper just grazes the top of it as it passes by.

- I got angular velocity from timing how long it took for the stopper to make 10 revolutions around the shaft.

- From the apparatus, I measured the height of the apparatus, the length of string, and the value of R.

II. Collected and analyzed data:

From 6 trials, I had data:

Then, I derived formula to calculate angle and angular speed from h.

I came up with 2 different ways to calculate angular speed.

Then, I entered my data into a sheet of Excel

And I graph omega based on h and omega based on period

Slope of the graph was the rate of omega based on period and omega based on h. In this graph, the slope was 1.0669, this mean omega based on h and omega based on period were pretty much same.

III. Conclusion:

From this experiment, I could see there were two ways to calculate angular velocity of a rotated motion: one based on h and one based on period. I also knew how to calculate angle which was made by the string and vertical line when the object rotate.