11/06/2014 Moment Of Inertia

Purpose:

The purpose of this lab is to find a spinning disk moment of inertia and measure the deceleration of the disk due to friction to predict the time for a cart attached to the disk with a wire to travel down a slope of some angle.

Experiment:

Part 1:

The first objective of the lab is to come up with a formula for the the angular acceleration of the spinning disk with friction which is as follows:

Tr - Tfriction = Ia

(Torque with respect to radius - torque of friction = inertia * angular acceleration)

We than measured the diameter of the outer and inner part of our disk.

We have the mass of the device which is labeled on the disk.

Next we calculated the inertia of the disk by adding the two types of cylinder which make up the disk we are using.

Here is the calculation from part 1:

Part 2:

Then we created the predicted formula for the acceleration of the cart which will travel down the slope.

Now we used logger pro and a camera to record the declaration of the spinning disk by it self by attaching a peace of tape on the edge of the disk and measure the time for the first revolution compared to the fourth revolution to determine the declaration due to friction.

Here is the camera we used to measure the rotations with logger pro:

Then with all the information gather we where able to predict the time it would take for the cart of 500g attached to the spinning disk to travel down the known distance which we measured with a known angle which we measured.

Here is our calculation from part 2:

Here is our experiment setup of the cart attached to the disk with the ramp:

Our predicted time was 9.2 second and our actual time measured with a stop watch was 9.73 seconds.