Lab 18: Moment of Inertia and Frictional Torque

Lab 18: Moment of Inertia and Frictional Torque

Introduction:

In this lab, we find the moment of inertia of a rotating non uniform disk, and then also find the frictional torque on its axles. Once we have this information, we could then predict how long it would take a cart to slide down an angled track. 

Apparatus/Procedure:

For this lab, we used a large pulley, a cart, a track, and various calipers. We followed the procedure described in the lab manual and took almost every measurement we could. We then calculated the moment of inertia of the pulley by adding the moments of inertia of each individual piece. Once we had this information, we then calculated our frictional torque by taking a slow motion video of the pulley slowing down and then analyzed it in Logger Pro. We took the slope of the velocity to find the angular deceleration α. These calculations and graphs are all located below. Once we found that, we could then estimate the time a 500 gram cart on a 40 degree incline would take to travel a meter. We then found the actual time it took and compared the two. 

Data/Calculations:

Calculating total inertia.

Graph used to find angular deceleration.

Calculating frictional torque.

Predicting time the cart will take to travel 1 meter at 40 degrees. The cart weighs 500 grams. 

Conclusion:

With a error of only 0.67% our experiment was a great success. Even with the relative inaccuracies of our measurements our time was very close to actual values.