PASCO PS-2120A Rotary Motion Sensor - Manual (Page 16)

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R o t a r y M o t i o n S e n s o r E x p e r i m e n t 3 : C o n s e r v a t i o n o f A n g u l a r M o m e n t u m
16 E x p e r i m e n t G u i d e
Setup
1. Mount the Rotary Motion Sensor to a support rod and
connect it to the interface. Place the disk directly on the
pulley as shown in Figure 3.1.
2. In the data acquisition software, create an experiment to
measure the angular velocity (in radians per second)
versus time (in second) of the disk before and after the
ring is dropped on top of it.
• In PASCO Capstone, for example, drag the Graph icon
from the Displays palette to the workbook. Select
“Angular Velocity (rad/s)” for the vertical axis, and
“Time (s)” for the horizontal axis.
Procedure
1. Hold the ring with the pins facing up just above the cen-
ter of the disk.
2. Give the disk a spin with your hand and click Record to
begin recording data.
3. After about 25 data points have been recorded, drop the
ring on the spinning disk. See Figure 3.2.
4. Click Stop to end data recording after the disk and ring
have made a few rotations..
5. In the Graph display, select the region of the data that
represents when the ring was dropped onto the disk.
6. In the Graph display, select the data analysis tool that
shows the coordinates of any point in the plot of data
and move the cursor to the data point that is immediately before the collision. Record the Angular Velocity
at this point as the initial angular velocity in Data Table 1.
7. Move the cursor to the data point immediately after the collision. Record the Angular Velocity at this point
as the final angular velocity in Data Table 1.
8. Weigh the ring and disk and record their masses. Measure the inner and outer radii of the ring, and the radius
of the disk. Record these values in Data Table 1.
Analysis
1. Calculate the theoretical value for the final angular velocity and record this value in the Data Table.
2. Calculate the percent difference between the experimental and theoretical values of the final angular veloc-
ity and record it in the Data Table.
Questions
1. How does the experimental result for the final angular velocity compare with the theoretical value for the
final angular velocity?
Figure 3.1: Setup for Dropping Ring onto Disk
Disk
Support
Rod
RMS with
3-step Pulley
Figure 3.2: Drop Ring onto Disk
Ring