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M o d e l N o . M E - 9 8 9 2
E x p e r i m e n t 2 : C o n s e r v a t i o n o f M o m e n t u m a n d E n e r g y
11
Procedure
1.
Load the launcher and push the ball in to the third (fastest) position.
2.
Move the pendulum into the vertical position. If it does not stay that way by
itself, hold it very lightly with one finger.
3.
Start data collection.
4.
Launch the ball so that it is caught by pendulum.
5.
After the pendulum has swung out and back, stop data collection.
6.
Note the maximum angular displacement measured by the RMS. Record it in
Table 2.1
7.
Record the initial angular velocity (just after the collision) in Table 2.1. Because
this velocity occurs close to the collision, the RMS cannot measure it accurately.
Instead, note the maximum
negative
velocity that occurs when the pendulum
swings back toward the launcher (record it as a positive value). Though this
might be slightly smaller than the actual initial velocity (due to friction), it is a
more reliable measurement.
8.
Repeat steps 1 through 7 several times.
9.
Calculate the average maximum displacement (
max
) and the average initial
velocity (
0
).
10.
Measure the mass of the ball.
m
ball
= _____________________
11.
Fire the ball into the catcher one more time (without recording data). Catch the
pendulum near the top of its swing so it does not swing back and hit the launcher
(this will prevent the ball from falling out or shifting).
12.
Measure the distance, , from the center of rotation (where the pendulum attaches
to the RMS) to the center of ball. = _____________________
Part 3: Determine Rotational Inertia of Pendulum-ball System
Set-up
1.
Remove the RMS from the mounting rod. (Leave the pendulum attached to the
RMS and leave the ball in the catcher.)
Table 2.1: Angular Displacement and Velocity
Trial
Maximum
Angle
Initial Angular
Velocity
Trial 1
Trial 2
Trial 3
Trial 4
Trial 5
Trial 6
Average:
max
=
0
=
