PASCO CI-6538 Rotary Motion Sensor - Manual (Page 21)

Rotary Motion Sensor Model No. CI-6538
20 ®
b) Measure the Radius
1. Using calipers, measure the diameter of the pulley about which the thread
is wrapped and calculate the radius. Record in Table 1.2.
c) Finding the Acceleration of the Apparatus Alone
In part IIa, “Finding the Acceleration of the Point Mass and Apparatus,”
the apparatus is rotating and contributing to the rotational inertia. It is
necessary to determine the acceleration and the rotational inertia of the
apparatus by itself, so this rotational inertia can be subtracted from the
total, leaving only the rotational inertia of the point masses.
1. Take the point masses off the rod and repeat the procedure under “Finding
the Acceleration of the Point Mass and Apparatus” for the apparatus
alone. You may need to decrease the amount of the hanging mass, so that
the apparatus does not accelerate so fast that the computer cannot keep up
with the data collection rate.
2. Record the data in Table 1.2.
Calculations:
1. Calculate the experimental value of the rotational inertia of the point masses
and apparatus together and record in Table 1.3.
2. Calculate the experimental value of the rotational inertia of the apparatus
alone. Record in Table 1.3
3. Subtract the rotational inertia of the apparatus from the combined
rotational inertia of the point masses and apparatus. This will be the
rotational inertia of the point masses alone. Record in Table 1.3.
4. Calculate the theoretical value of the rotational inertia of the point masses.
Record in Table 1.3.
Point Mass and
Apparatus
Apparatus
Alone
Hanging Mass
Slope
Radius
Table 1.2: Experimental Rotational Inertia Data