PASCO ME-9892 User Manual
®
Instruction Manual with
Experiment Guide
012-09842B
*012-09842*
Ballistic Pendulum Accessory
ME-9892
Ballistic Pendulum Accessory Table of Contents
Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Equipment Set-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Assemble the Apparatus, 4
Load the Launcher, 5
Prepare the Sensor, 6
Test Fire, 6
Foam Insert Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Experiment 1: Ballistic Pendulum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Theory, 7
Experiment Set-up, 7
Procedure, 7
Analysis, 9
Question, 9
Further Study, 9
Experiment 2: Conservation of Momentum and Energy . . . . . . . . . . . . . . . . . . . . . . . . 10
Background, 10
Part 1: Measure Launch Velocity, 10
Part 2: Record Ballistic Pendulum Data, 10
Part 3: Determine Rotational Inertia of Pendulum-ball System, 11
Analysis, 13
Questions, 13
Further Study I: Different Launch Speeds, 14
Further Study II: Different Projectile Mass, 14
Further Study III: Different Center of Mass, 14
Further Study IV: Elastic Collision, 14
Further Study V: Alternative Determination of Rotational Inertia, 15
Further Study VI: Horizontal Collision, 16
Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Ballistic Pendulum Accessory
®
1
2
3
4
5
6
7
ME-9892
Included Equipment Part Number
1. Catcher and pendulum
ME-9892
rod
2. Pendulum attachment
613-076
screw
3. Replaceable foam
ME-9894 (5-pack)
insert
4. Ballast mass 648-06511
5. Ballast lock nut 614-029
6. Ballast fastening screw 617-027
7. Steel ball ME-9864 (4-pack)
Required Equipment
Short Range Launcher ME-6800
PASPORT Rotary Motion
Sensor with three-step
1
pulley
Table Clamp ME-9472 or similar
PS-2120
90 cm mounting rod ME-8738 or similar
C-clamp SE-7286 or similar
Optional Equipment Part Number
Photogates (qty. 2)
Digital Adapter
2
1, 2
Photogate Mounting
Bracket
2
Super Pulley with Clamp
Hanging mass
2
Mini Rotational Accessory
Spherical Mass Set
Additional three-step
pulley
5
45 cm mounting rod
Multi clamp
1
Sensor requires a PASPORT interface.
2
For measuring launch velocity and rotational inertial. See
Experiment 2, page 10.
3
Required for experiment 2
4
For Experiment 2, Further Study II: Different Projectile Mass
(page 14)
5
For Experiment 2, Further Study VI: Horizontal Collision
(page 16)
5
4
5
ME-9498A or similar
PS-2159
ME-6821
2
ME-9448A
ME-9348 or similar
3
CI-6691
ME-8968
CI-6693
ME-8736 or similar
SE-9442 or similar
3
®
Ballistic Pendulum Accessory Introduction
Three-step
pulley
Figure 2: Three-step
pulley on RMS
Introduction
Use the Ballistic Pendulum Accessory in combination with a Short Range Launcher
and Rotary Motion Sensor (RMS) to measure the velocity of a steel ball and study
rotational collisions. The launcher shoots the ball into the Ballistic Pendulum Accessory. The RMS measures the resulting angular displacement and velocity of the pendulum. The pendulum can be configured to catch the ball or allow the ball to bounce
off. With the addition of the Mini Rotational Accessory, the apparatus can be configured as a physical pendulum or rotational system with adjustable moment of inertia.
This manual includes set-up instructions and experiment instructions.
Equipment Set-up
Assemble the Apparatus
1. Set up the launcher, C-clamp, table clamp, mounting rod, and RMS as shown in
Figure 1. The exact position of the RMS is not important yet. Note that the side
of the RMS without the model number on the label is facing you. (If the RMS is
mounted the other way, it will measure negative displacement.)
ä
FOR
INTERFACES
ROTARY MOTION SENSOR
Figure 1: Launcher and RMS mounted on rod
2. Slide the three-step pulley onto the RMS shaft with the largest pulley out as
shown in Figure 2.
4
®
Model No. ME-9892 Equipment Set-up
End
hole
Attachment
screw
Center hole
Figure 3: Attachment
screw loosely captured
in center hole
Align rod with tabs
Figure 5: Pendulum
aligned with launcher,
catcher side (top) and
bumper side (bottom)
PushrodBall
Swing pendulum
out of the way
3. Select one of the holes on the pendulum rod: either the center hole or the end
hole. Also select a side of the pendulum: either the catcher or the bumper. Thread
the attachment screw into the hole as shown in Figure 3. Screw it all the way in
so it is loosely captured.
4. Thread the screw into the end of the RMS shaft. Align the pendulum rod with the
tabs on the pulley as shown in Figure 4. Tighten the screw.
Figure 4: Attaching pendulum to RMS
5. Adjust the position of the RMS so the pendulum is aligned with the launcher as
shown in Figure 5. Leave a 2.5 cm gap between the launcher and the pendulum.
Load the Launcher
1. Swing the pendulum out of the way as shown in Figure 6.
2. Place the steel ball in the end of the barrel.
Caution: Use extra caution when using the launcher with a steel ball. Do not look down
the barrel. Do not leave the launcher loaded and unattended.
3. Use the pushrod included with the launcher to push the ball down the barrel until
the trigger catches in the first, second, or third position (for a slow, medium, or
fast launch).
Figure 6: Loading the launcher
5
®
Ballistic Pendulum Accessory Foam Insert Replacement
Figure 7: Typical data
4. Return pendulum to its normal hanging position.
Prepare the Sensor
1. Connect the RMS to a PASPORT interface. If you will be using a computer, connect the interface to it and start your data collection software.
2. Set the sampling rate of the RMS to 40 Hz.
3. Prepare a graph to show angular position versus time.
For detailed instructions, refer to the documentation that came with your interface or
press F1 to launch the software’s on-line help.
Test Fire
1. Start data recording.
2. Pull the trigger of the launcher.
3. Stop data collection.
Figure 7 shows typical data for an inelastic collision. If your data shows negative
angular displacement, disassemble the RMS from the mounting rod and pendulum
and remount it with the pendulum attached to the other end of the RMS shaft.
Foam Insert Replacement
With age and repeated use, the foam catcher insert may lose elasticity. If the catcher
does not reliably hold the ball, remove the foam insert and replace it with a new one
(PASCO part ME-9894 is a five pack of foam inserts).
Figure 8: Removable foam insert
6
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