PASCO ME-9833 Physical Pendulum Set User Manual

Page 18

Model No. ME-9833

Physical Pendulum Set

2. Select a region of the first run of angular velocity data and select ‘Linear Fit’ from the

‘Fit’ menu.

3. Record the value of the slope as the first value of angular acceleration around the center

of gravity.

4. Repeat the process for the other two runs of data.

5. Find the average angular acceleration,

, and record it in the Data Section.

6. Calculate the net torque,

τ = rm(g - rα).

7. Calculate the moment of inertia about the center of gravity by dividing the net torque by

the average angular acceleration. Record the result as the moment of inertia about the
center of gravity, I

. (

)

8. Determine the percent difference between the calculated moment of inertia and the

measured moment of inertia and record the result in the Data Section.

Questions

1. How does your value for the calculated moment of inertia compare to the measured moment

of inertia?

2. Do your results support or disprove the idea that the moment of inertia of a physical

pendulum can be determined from its period of oscillation. Why or why not?

Extensions

Repeat the procedure for the thin ring, thick ring, and offset hole. To measure the moment of inertia
of the thin ring, for example, fasten it to the top of the solid disk, find the combined moment of
inertia and then subtract the moment of inertia of the solid disk.

Table 2: Data Section

Item

Value

Item

Value

Mass of solid disk, M:

Mass of hanger, m:

Distance from pivot to center of
gravity, L

Average angular acceleration,

Average measured period of
oscillation, T:

Torque,

τ:

Calculated value for moment of
inertia, I:

Measured value for moment of
inertia, I:

Radius of step pulley, r:

Percent difference:

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