To understand the effects on the angular acceleration when various changes are applied to our apparatus.
This is accomplished by applying a known torque to our apparatus and measuring the angular acceleration.
Apparatus:
Experiment:
We began with the physical measurements such as the dimensions of our disks, pulleys, and the mass of any relevant parts.
The radius and mass of the top steel disk - 63.3-mm, 1356-g
The radius and mass of the bottom steel disk - 63.3-mm, 1348-g
The radius and mass of the top aluminum disk - 63.3-mm, 466-g
The radius and mass of the smaller torque pulley - 12.5-mm, 10.0-g
The radius and mass of the larger torque pulley - 25.0-mm, 32.0-g
The mass of the hanging-mass supplied with the apparatus - 24.5-g
Using logger pro we set up the Pasco rotational sensor by changing the sensor settings to 200 counts per rotation.
To measure the acceleration, we analysed the graphs** of the angular acceleration of the disk as the hanging mass moved downward, then we analysed it as the hanging mass moved upward. We took the average of the two values for each experiment and used these values for comparison.
The resulting measurements are as follows (variations underlined) -
Expt.#1, α = 0.6239-rad/sec^2
Hanging mass only, with small pulley and top steel disk.
Expt.#2, α = 1.255-rad/sec^2
Doubled hanging mass, with small pulley and top steel disk.
Expt.#3, α = 1.884-rad/sec^2
Tripled hanging mass, with small pulley and top steel disk.
Expt.#4, α = 1.221-rad/sec^2
Hanging mass only, with large pulley and top steel disk.
Expt.#5, α = 3.457-rad/sec^2
Hanging mass only, with large pulley and top aluminum disk.
**Graphs for this activity were lost due to a flash-drive malfunction.
Conclusion (observations):
When we doubled the mass of the hanging mass from 24.5-g to 50-g, we observe that the value for α is approximately doubled from 0.6239-rad/sec^2 to 1.255-rad/sec^2.
When we tripled the mass of the hanging mass from 24.5-g to 75-g, we observe that the value for α is approximately tripled from 0.6239-rad/sec^2 to 1.884-rad/sec^2.
When we doubled the radius of the torque pulley from 12.5-mm to 25.0-mm, we observe that the value for α is approximately doubled from 0.6239-rad/sec^2 to 1.221-rad/sec^2.
When we changed the top disk from steel to aluminum, we decreased the mass of the disk by factor of about 3 from 1356-g to 466-g. We observe that the value for α is approximately tripled from 1.221-rad/sec^2 to 3.457-rad/sec^2.
A Great Day for Physics.
(10/29/14, 7:02am)
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