Students are asked to perform an experiment to determine I, the rotational inertia of a T-shaped PVC apparatus, in the lab
using the setup shown. They are expected to find I by plotting their data in a graph. The students have access to equipment
commonly found in a high school physics laboratory, but the experiment must use the setup as shown above which
includes a T-shaped PVC apparatus which rotates on a ring stand. The system is accelerated by a hanging object on the
end of a string.
(A) Briefly identify each quantity to be measured, the symbol used to represent that quantity, and the equipment that
would be used to measure the quantity.
(B) Briefly describe the procedure to be used to determine the rotational inertia. Provide enough detail so that another
student could replicate the experiment, including any steps necessary to reduce experimental uncertainty. As
needed, use the symbols defined part (A).
(C) Which quantities calculated from your measurements in part (B) could be graphed on the horizontal and vertical
axes to produce a graph that would be used to determine the rotational inertia? Explain how you would use your
measurements to calculate the quantities you would graph.
(D) Describe what information from the graph described in part (D) would be used and how it would be used to
determine the rotational inertia.
(E) The students calculate the torque from the string and the angular acceleration of the PVC from each data point.
They graph t vs a and notice a non-zero vertical intercept. What is the physical meaning of this intercept?