PASCO ME-6829 User Manual

Instruction Manual with

Experiment Guide

012-09851A

Mini Launcher Ballistic Pendulum

ME-6829

Mini Launcher Ballistic Pendulum Table of Contents

Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Equipment Set-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Foam Insert Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Experiment 1: Inelastic Collisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Experiment 2: Ballistic Pendulum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Experiment 3: Conservation of Momentum and Energy . . . . . . . . . . . . . . . . . . . . . . . . 12

Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Mini Launcher Ballistic Pendulum

ME-6829

Included Equipment Part Number

1. Catcher and pendulum rod ME-6829

2. Sliding counterweight 648-09595

3. Counterweight set screw 613-047

4. Pendulum attachment

613-076

screw

5. Replaceable foam insert ME-6835 (5-pack)

6. Ballast mass 648-06511

7. Ballast lock nut 614-029

8. Ballast fastening screw 611-043

Required Equipment Part Number

Mini Launcher

(includes

ME-6825A

projectile)

PASPORT Rotary Motion

Sensor with three-step

pulley

PS-2120

Table Clamp ME-9472,

or similar

90 cm mounting rod ME-8738,

or similar

Optional Equipment

Photogates (qty. 2) ME-9498A,

or similar

Digital Adapter

PS-2159

Photogate Mounting Bracket ME-6821

Super Pulley with Clamp ME-9448A

Hanging mass ME-9348,

or similar

The new-style mounting bracket included with model ME-6825A is required. If you have an older mini launcher (model ME-6825), upgrade it with a model ME-6836 bracket.

Sensor requires a PASPORT interface.

For measuring launch velocity and rotational inertial. See Experiment 3.

Mini Launcher Ballistic Pendulum Introduction

Introduction

Use the Mini Launcher Ballistic Pendulum in combination with a Mini Launcher and Rotary Motion Sensor (RMS) to measure the velocity of a steel ball. The Mini Launcher shoots the ball into the Mini Launcher Ballistic Pendulum. 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. Two pivot locations and removable masses allow it to approximate a simple pendulum or a physical pendulum.

This manual includes set-up instructions and experiment instructions ranging from a simple (Experiment 1) to more advanced (Experiment 3).

Equipment Set-up

Assemble the Apparatus

1. Set up the mini launcher, bracket, 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.)

FOR

INTERFACES

ROTARY MOTION SENSOR

Mini Launcher

Bracket

Table clamp

Figure 1: Launcher and RMS mounted on rod

RMS

Mounting Rod

Three-step

pulley

2. Slide the three-step pulley onto the RMS shaft with the largest pulley out as

shown in Figure 2.

Figure 2: Three-step

pulley on RMS

Model No. ME-6829 Equipment Set-up

3. Select one of the holes on the pendulum rod: either the center hole or the end

hole. If you will be using the end hole, remove the counterweight. Also select a

End hole

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.

Attachment

screw

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.

Align rod with tabs

Center hole

Figure 3: Attachment

screw loosely captured

in center hole

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.

Load the Launcher

1. Swing the pendulum out of the way as shown in Figure 6.

2. Place the projectile (included with the launcher) in the end of the barrel.

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).

Swing pendulum

out of the way

Figure 5: Pendulum aligned with launcher, catcher side (top) and bumper side (bottom)

PushrodBall

Figure 6: Loading the launcher

Mini Launcher Ballistic Pendulum Foam Insert Replacement

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, con-

nect the interface to it and start DataStudio.

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 DataStudio’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-6835).

Figure 7: Typical data

Figure 8: Removable foam insert

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