blog 14

The goal of this lab is to determine the moment of inertia of a triangle with different orientations.

To do this, we again use a frictionless spinning disk apparatus as we did in our previous moment of inertia experiment. This time, however, we attach a small metal triangle to the top of our spinning object as shown below.

Before we ran an experement to determine moment of inertia of our triangle, we first derived its theoretical moment of inertia as shown below

We arrive at a value for inertia of the triangle about its center of mass

with the 0.15 m side down= 0.184

and with the other side down =0.098

To determine a value experimentally, we used the F=ma and T=I(alpha) forms of newtons second law as shown above to determine an equation for center of mass as a function of alpha. Running the experiment on the first orientation of the triangle, we get a value of I of

I=0.1843

which is only about 1 percent off of our predictied value. Due to time constraints, we were unable to test the other orientation of the triangle experimentally, However from our first result it seems probable that our model is fairly accurate, with the small discrepancy between our expected and acutual values probably due to the small amount of friction in the pulley and spinning mass apparatus.