Moment of Inertia

Photo of the lab
Photo of the lab
Photo of the lab
Photo of the lab

This lab is designed so that students can experience the concept of what does the moment of inertia mean?

The lab involves a meter stick, two identical clamps and a stop watch. A student holds the meter stick horizontally at the 50 cm mark with their arms extended. They then oscillate the meter stick from the horizontal to the vertical and back to the horizontal. The goal is to get as many of these oscillations as possible in a 5 second interval. One student checks the time and the other counts the number of oscillations. Next identical clamps are placed 10 cm on either side of the middle. The above procedure is then repeated. The clamps are again moved out 10 cm, and the number of oscillations in 5 seconds is timed. The clamps are moved out in 10 cm intervals with the number of oscillations for each location measured. The students then plot the period of the oscillations (1/ # of oscillations in 5 seconds) versus the radius at which the clamps are placed. The students then fit a polynomial to their data and observe that for each student that the trend is quadratic, just as one would expect in order to overcome rotational inertia.

Besides observing the trend in the data, each student feels what the moment of inertia means as they feel what happens as the masses is moved outward. This is a very good hands-on activity.

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