A string was wrapped around the torque pulley above the flywheels and hung over a pulley which suspended a 24.6g weight. There were three flywheels we used in our experiments; two steel and one aluminum. For each trial there was a steel flywheel on the bottom and either a steel or aluminum flywheel on the top. The steel flywheel on the bottom had a mass of 1.348kg and the top steel flywheel had a mass of 1.357kg. The aluminum flywheel had a mass of 0.466kg. All the flywheels had diameters of 12.65cm. Other options for components were a large torque pulley with mass 36g and diameter 5cm and a small torque pulley with mass 9.9g and diameter 2.5cm. On the top was a pin that stopped the flow of air from going out the top.
Also used in this lab was a Lab Pro and Laptop to count the lines on the top flywheel as it spins. After following the instructions for the setup of Logger Pro in the lab handout, the hose clamp on the bottom of the apparatus was left open to allow the top flywheel to spin freely.
The air was then turned on to a moderate level and a test run was performed to make sure things went as we wanted them to. The first trial had the two steel flywheels and a small torque pulley with the 24.6g weight hanging. Here is a picture of the experiment.
The alpha down is 0.1470rad/s^2 and the alpha up is 0.1648rad/s^2 with their average being 0.1559rad/s^2.
The second experiment was doubling the mass with the same components. Below is a picture of the experiment.
Alpha down is 0.2985rad/s^2 and alpha up is 0.3315rad/s^2 with their average of 0.315rad/s^2.
The third experiment saw triple the mass with the same components. An image of the trial is below.
The alpha down is 0.4467rad/s^2 with alpha up 0.4852rad/s^2 and an average of 0.466rad/s^2.
The fourth trial changed the torque pulley but kept the steel flywheels with 24.6g hanging only. Here is a picture of the trial.
The alpha down here is 0.2843rad/s^2 and alpha up is 0.3253rad/s^2 with their average of 0.3048rad/s^2.
The fifth trial only had the top flywheel changed out to the aluminum flywheel with 24.6g hanging and a large torque pulley. Below is the trial picture.
Here alpha down is 0.8033rad/s^2 and alpha up is 0.9191rad/s^2 and their average is 0.8612rad/s^2.
The last trial had both the steel flywheels spinning with the large torque pulley and 24.6g of mass hanging. Heres a picture of the trial.
The alpha down is 0.1438rad/s^2 and alpha up is 0.1615rad/s^2 and their average is 0.1527rad/s^2.
It seems that changing the mass to twice and three times its values increased the values of alpha by its respective increase. Trial two's alpha with twice the mass is twice the alpha of trial one. The same can be said of trial 3. When the torque pulley was increased to the larger pulley, more torque was applied to the system which resulted in a larger value of alpha due to the relation of torque=moment of inertia times alpha. With an increase in the torque, the alpha must also increase since moment of inertia stays the same. When a lighter flywheel was substituted for the top flywheel, the moment of inertia was reduced so the alpha had to increase because the torque was the same value with only 24.6g hanging. The opposite happened when both steel flywheels were spinning and caused the moment of inertia to increase dramatically with the torque staying the same the alpha had to be reduced.
Using the derivations from the lab manual, the moment of inertia for can be found with respect to the hanging mass, the radius of the torque pulley and the value of alpha.
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