PASCO ME-9207B User Manual

012-05760B Free Fall Adapter

Instruction Manual and
Experiment Guide for
the PASCO scientific
Model ME-9207B

FREE FALL ADAPTER

012-05760B

4/99

© 1995 PASCO scientific $7.50

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Free Fall Adapter 012-05760B

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012-05760B Free Fall Adapter

T able of Contents

Section..........................................................................................................Page

Copyright, Warranty, and Equipment Return.....................................................iv

Introduction.......................................................................................................1

Equipment.........................................................................................................1

Operation........................................................................................................2-3

Troubleshooting................................................................................................3

Experiment: Measuring g.................................................................................4-5

Suggested Additional Experiments.....................................................................5

Appendix A: Options for using the ME-9207A.................................................6

Appendix B: Connecting to Computer Interfaces...............................................7

Appendix C: Technical Data.............................................................................8

Technical Support...................................................................................Back Cover

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Free Fall Adapter 012-05760B

Copyright, Warranty, and Equipment Return

Please—Feel free to duplicate this manual
subject to the copyright restrictions below.

Copyright Notice

The PASCO scientific 012-05760 Model ME-9207B
Free Fall Adapter manual is copyrighted and all rights
reserved. However, permission is granted to non-profit
educational institutions for reproduction of any part of
the manual providing the reproductions are used only for
their laboratories and are not sold for profit. Reproduc­tion under any other circumstances, without the written
consent of PASCO scientific, is prohibited.

Limited Warranty

PASCO scientific warrants the product to be free from
defects in materials and workmanship for a period of
one year from the date of shipment to the customer.
PASCO will repair or replace at its option any part of
the product which is deemed to be defective in material
or workmanship. The warranty does not cover damage
to the product caused by abuse or improper use. Deter­mination of whether a product failure is the result of a
manufacturing defect or improper use by the customer
shall be made solely by PASCO scientific. Responsibil­ity for the return of equipment for warranty repair
belongs to the customer. Equipment must be properly
packed to prevent damage and shipped postage or
freight prepaid. (Damage caused by improper packing of
the equipment for return shipment will not be covered
by the warranty.) Shipping costs for returning the
equipment after repair will be paid by PASCO scientific.

Equipment Return

Should the product have to be returned to PASCO
scientific for any reason, notify PASCO scientific by letter,
phone, or fax BEFORE returning the product. Upon
notification, the return authorization and shipping instruc­tions will be promptly issued.

ä

NOTE: NO EQUIPMENT WILL BE

ACCEPTED FOR RETURN WITHOUT AN
AUTHORIZATION FROM PASCO.

When returning equipmenmt for repair, the units must
be packed properly. Carriers will not accept responsi­bility for damage caused by improper packing. To be
certain the unit will not be damaged in shipment,
observe the following rules:

➀The packing carton must be strong enough for the

item shipped.

➁Make certain there are at least two inches of

packing material between any point on the appara­tus and the inside walls of the carton.

➂Make certain that the packing material cannot shift

in the box or become compressed, allowing the
instrument come in contact with the packing
carton.

Address: PASCO scientific

10101 Foothills Blvd.
Roseville, CA 95747-7100

Phone: [phone]
FAX: [phone]
email: [e-mail]
web: www.pasco.com

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012-05760B Free Fall Adapter

Introduction

The PASCO Model ME-9207B Free Fall Adapter is an
automatic release mechanism that plugs into PASCO
Photogate Timers, Smart Timer, ScienceWorkshop

®

computer interfaces, and other electronic timing
devices, allowing you to measure the acceleration due
to gravity (g) with 1 percent accuracy. It is also easily
adapted for a variety of other mechanics experiments,
providing a highly accurate method for starting and
stopping the electronic timers. Some examples of
these other uses are provided at the end of this
manual.

Equipment

Equipment Included:

• Free Fall Adapter: (ball release mechanism, recep­tor pad, controller box, cable, and phone jack con­nector)

In the basic free fall experiment, a steel ball is
clamped into the spring loaded release mechanism.
The ball is in series with the triggering circuit for the
photogate timer. When the thumbscrew is turned, the
mechanism pops open, releasing the ball and starting
the timer. When the ball strikes the receptor pad, the
top plate of the pad is forced against the metal base.
This automatically stops the timer. The timer display
shows the time it took for the ball to drop from the re­lease mechanism to the pad.

ball release
mechanism

• 2 steel balls (1.27 cm diameter)

• 2 steel balls (1.91 cm diameter)

Additional Equipment Required:

• clamp (such as the PASCO SE-9446 Buret Clamp

• rod stand

• electronic timing device (such as the PASCO ME­9403 Photogate Timer, PASCO ME-8930 Smart
Timer, PASCO ScienceWorkshop® computer inter­face (500 or 700 series and CI-6500)

• metric stick

steel ball

controller box

phone plug

(Connect to

Photogate Timer)

receptor pad

Figure 1. Free Fall Adapter: Included Equipment

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Free Fall Adapter 012-05760B

Operation

Connecting the Free Fall Adapter to the
Electronic Timing Device

The Free Fall Adapter connects the any electronic
timing device by inserting the phone plug into a
phone jack on the device. See Appendix A for a
diagram of many of the connection options. See
Appendix B for illustrated connection instructions for
several of these timing devices.

Options for Electronic Timing

Options for electronic timing for the Free Fall
Adapter include the PASCO Photogate Timers
(Model 9206A, or 9215A), Smart Timer
(ME-8930), and ScienceWorkshop

®

computer in­terface (Series 500, 700, and CI-6500)V. If you
wish to use this adapter with other timers, please
see the Technical Information section (Appendix
C) for power supply, output signal, and connector
specifications.

Equipment Setup

1. Clamp the ball release mechanism to a lab stand, or

any other device that will hold it vertical and at the
desired height over the floor or table (Figure 2).

For best results, the drop height (d) should be the
full two meters allowed by the cable. Shorter
heights will work fine, but accuracy is reduced
proportionally.

2. Position the ball receptor plate directly under the

ball. (You might want to place the receptor plate
in a shallow box so the ball doesn’t roll away after
it falls.)

3. Insert one of the steel balls into the release mecha-

nism, pressing in the dowel pin so the ball is
clamped between the contact screw and the hole in
the release plate. Lightly tighten the thumbscrew
to lock the ball in place.

4 . Plug the phone jack into a port on your electronic

timing device.

Data Collection

The process for data collection varies with the elec­tronic timing device. The process for a few of these
devices is listed below:

PASCO Photogate Timer (ME-9206A or ME­9215A)

ball release
mechanism

Photogate Timer

(not included)

d

Figure 2. Equipment Setup

dowel pin

(press

here)

thumbscrew

on back side

contact screw

receptor pad

1. Turn the timer ON and set it in the GATE mode.

2. Tap the receptor pad to reset the Free Fall Timer

electronics.

3. Press the RESET button to reset the timer.

4. Loosen the thumbscrew to release the ball. It

should hit in the center of the receptor pad. If not,
reset the timer, reposition the pad, and try it again.

5. Read the time on the digital display of the timer.

This is the time it took for the ball to fall a distance

d, as shown in Figure 2.

PASCO Smart Timer (ME-8930

1. Press the Select Measurement button repeatedly

until Time is displayed.

2 . Press the Select Mode button repeatedly until the

Stopwatch mode is displayed.

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012-05760B Free Fall Adapter

Data Collection, continued

3. Press the Start/Stop button once.

Result: An asterisk will appear on the display in­dicting that the Smart Timer is ready to collect
Time of Fall data.

4. Loosen the thumbscrew to release the ball. It

should hit in the center of the receptor pad. If not,
reset the timer, reposition the pad, and try it again.
Result: The Smart Timer will display the time of
fall in seconds.

5. Read the time on the digital display of the timer.

This is the time it took for the ball to fall a distance
d, as shown in Figure 2.

6. To prepare to take another measurement,
reposition the ball in the ball release mechanism,
and press the Start/Stop button to reset the Smart
Timer.

PASCO ScienceWorkshop Computer Interfaces
(Series 500 and 700)

1 . Set up the Free Fall Adapter to be recorded in your

data acquisition software.
Note: Refer to the User Manual or on-line help for

details.

Note: In ScienceWorkshop, you can specify the
distance d for automatic calculation of acceleration
due to gravity (g). In DataStudio, g is calculated
automatically assuming d = 1 meter.

2 . Open an appropriate display for the data (such as

the Digits display in ScienceWorkshop
DataStudio™.

Note: In ScienceWorkshop and DataStudio, the
acceleration due to gravity is automatically
displayed if the appropriate display has been
opened.

3. Start recording data.

®

and

4. Loosen the thumbscrew to release the ball. It

should hit in the center of the receptor pad. If not,
reposition the pad, and try it again.
Result: The time of fall (s) will be displayed.
Acceleration due to gravity (g) (m/s/s) will also be
displayed if the appropriate display and conditions
have been set up as described above.

Troubleshooting

In Case of Difficulty

If the timer does not begin timing when the ball is re­leased or fails to stop timing when the ball hits the re­ceptor pad, check the following:

1. Check that the ball, or whatever object you are tim-

ing, makes electrical contact between the contact
screw and the flat-spring of the ball release. If nec­essary, clean the contact, flat-spring, and ball. (An
object made of plastic, wood, or another noncon­ductive material won't trigger the timer when re­leased.)

2. Check that the target pad does not touch the metal

base of the receptor pad but is close enough (1 to 2
mm) so that it will contact the metal base when the
falling object strikes it.

Problem with PASCO Photogate Timer:

➤ If your timer readout has missing or extra segments

or the timer will not count or keeps counting even
after checking the above conditions, then the bat­teries probably need replacement.

Problem with PASCO Computer Interfaces:

➤ Recent upgrades in the Precision Timer III and

Smart Pulley Timer software allow the user to
choose either our original ME-9207 or our newer
ME-9207A Free Fall Adapter. The instruction for
using the two models differs due to changes in the
circuitry. For further information on using the ME­9207 Free Fall Adapter with your software, or to
obtain a current edition of the software, contact the
technical support department at PASCO (1-800­772-8700).

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Free Fall Adapter 012-05760B

Experiment: Measuring g

Introduction

The equation of motion for a body starting from rest and undergoing constant acceleration can
be expressed as:

where x is the distance the object has traveled from its starting point, a is the acceleration, and
t is the time elapsed since the motion began.

In order to measure the acceleration caused by gravity, several questions must be answered:

•Is the acceleration constant? If it is, then the distance an object falls will be proportional to
the square of the elapsed time, as in the above equation.

•If the acceleration is constant, what is the value of the acceleration? Is it the same for all
objects or does it vary with mass or size of the object, or with some other quality of the ob­ject? If it is not constant, how does it vary with time?

In this experiment you will answer these questions by carefully timing the fall of a steel ball
from various heights.

x =

2

a

2

Procedure

1. Set up the Free Fall Timer as described in the SETUP and OPERATION section of this manual.

Use the 13 mm diameter steel ball.

2. Set d, the height from which the ball drops, to approximately 2.0 meters. Measure the distance

as accurately as possible and record the distance in Table 1. Follow the instructions for the
Timer or Computer Interface as given in the “Operations” section. Record the measured time
as t

in Table 1. Repeat the measurement at least four more times and record these values as t2-

1

t5. Calculate the average of your five measured times and record this value as t

avg

.

3. Set d to 1.75, 1.50, 1.25, 1.00, 0.75 and 0.50 m, repeating step 2 for each value of d. (The

actual value of d need not correspond exactly to the listed values, but be sure you measure it
carefully.)

4. Repeat steps 2 and 3 using the 16 mm steel ball.

Analysis

For each ball, plot a graph of d versus t
limits of your experimental accuracy, do your data points define a straight line for each ball?
Was the acceleration constant for each ball?

Table 1 Data and Calculations

d (m) t

1

t

2

2

with d as the dependent value (y-axis). Within the

avg

t

3

t

4

t

5

t

avg

2

t

avg

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012-05760B Free Fall Adapter

If your graphs were linear, measure the slope of each graph. Using your measured slopes
and the equation shown in the introduction to this experiment, determine the acceleration
caused by gravity. Be sure to include the units. Was the acceleration the same for each
ball?

Conclusion

Describe your laboratory experiment and discuss your results. Consider the following
questions: (1) Is the acceleration caused by gravity constant? (2) Is the acceleration
caused by gravity the same for all objects? Discuss the conditions under which you be­lieve your results to be true. Include a discussion of the errors in your measurements and
how they affect your conclusions. How linear was your graph? How might you alter
your technique, or the experiment, in order to reduce experimental errors?

Suggested Additional Experiments

The Free Fall Apparatus can bring high resolution
timing to a variety of mechanics experiments. Any
conductive object can be timed as long as it can be
clamped in the release mechanism and is heavy enough
to depress the receptor plate when it strikes. The

Atwood’s Machine

Investigate F=ma
using a highly
accurate Atwood’s
Machine.

illustrations below show some examples of
experimental setups.

We'd like to thank Giles Shepherd of Everett Com­munity College for suggesting the experiments
shown below.

Inclined Plane 2

Compare the velocities of a solid disk and a
ring as they roll down an inclined plane.

Ring Stand

Inclined Plane 1

Determine the acceleration of a cart pulled by

a constant force on a flat or inclined surface.

A short screw through
the hole in the release
plate will help hold the
cylinder in the release
mechanism.

metal disk
or ring

inclined plane

receptor pad

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Free Fall Adapter 012-05760B

Appendix A: Options for using the

ME-9207B Free Fall Adapter

Photogate Timer
ME-9206A or
ME-9215A

AI-6501
Computer Interface
(AppleII, IIe, IIGS)

ME-9207B
Free Fall
Adapter

Smart Timer
ME-8930

Apple Computer

IBM - Compatible
Computer

PT III
SPT
IDS Timer

PT
SPT
IDS Timer

AI-6575 Game Port
Interface Box
(AppleII, IIe, IIGS)

ME-9343A Apple
Adapter Cable
(AppleIIe, IIc, IIGS)

ScienceWorkshop

Interfaces (500 and
700 Series)

CI-6500
Computer Interface
(Non-MCA)

CI-6588 Game Port
Interface Box
(requires 15 pin
game port)

ME-9402 IBM
Adapter Cable
(requires 15 pin
game port)

Mac Timer

Macintosh
Computer

Science
Workshop

PT III = Precision Timer III (Apple II)
SPT = Smart Pulley Timer
PT = Precision Timer (MS-DOS)
IDS = Introductory Dynamics System

PASCO has an IBM gameport
interface card available, SE-6590

6

CI-6700
Mac Timer
Interface

CI-6550
Mac 65
Interface

ScienceWorkshop

Interfaces (500 and
700 Series)

012-05760B Free Fall Adapter

Appendix B: Connecting to Computer Interfaces

Using the AI-6575 Apple Gameport Interface:

Connect the ME-9207B Free Fall Adapter into
connector 1 on the Gameport interface box as shown
in Figure 3.

Inside Apple

II+ or IIe

Game-

Figure 3

Gameport Interface

port

Phone Plug

from Free Fall

Adapter

Using the ME-9343A Adapter Cable:

Connect the ME-9207B Free Fall Adapter into con­nector 1 on the ME-9343A (the connector with the
black shrink-wrap marking) as shown in Figure 4.

Using the CI-6588 IBM PC Gameport
Interface:

Connect the ME-9207B Free Fall Adapter into
connector 1 on the IBM Gameport interface box as
shown in Figure 5.

15-Pin

Connector

Back of IBM

Computer

Figure 5

Gameport Interface

1432

Stereo Phone

Plug from

Free Fall

Adapter

Gameport

Using the ME-9402 IBM Adapter Cable:

Connect the Free Fall Adapter into the jack with the black
tape.

Stereo Phone

Plug from Free

Fall Adapter

Gameport

9-Pin Connector

Adapter Cable

Figure 4

Using the AI-6501 or CI-6500 Series 6500
Computer Interface:

Connect the Free Fall adapter to digital input 1 on the
Series 6500 interface box.

Plug from

Free Fall

Adapter

CI-6510 SIGNAL INTERFACE

FOR USE WITH PASCO SERIES 6500 SENSORS

DIGITAL CHANNELS

1234

PASCO

SERIES

6500

INTERFACE

SYSTEM

CI-6510 SIGNAL INTERFACE

Digital Input 1

ON

ANALOG CHANNELS

A s

GAIN = 1,10,100

ISOLATED

Ribbon Cable

to Computer

B n C l

=

GAIN

1

GAIN = 1

ISOLATED

REF TO GND

15-Pin Game
Port Interface

Card

15-Pin

Connector

Adapter Cable

Back of IBM Computer

Figure 6

Using the ScienceWorkshop 500 Computer
Interface

Connect the Free Fall Adapter to digital input 1 on the
interface.

Phone Plug

from Free Fall

Digital Input 1

Adapter

Figure 7

Figure 8

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Free Fall Adapter 012-05760B

Appendix C: T echnical Data

Timer Specifications for the Free Fall
Adapter

The PASCO ME-9207B Free Fall Adapter can be used
with any timer that will:

1 . Provide 5 VDC at 50 mA.
2 . Provide a minimum resolution of 1 ms.

3. Begin counting on the negative slope of a pulse
and stop counting on the positive slope of the
pulse.

The connections for the stereo phone jack are indi­cated in Figure 6. The schematic is shown below.

ä

NOTE: All resistors are 1/4 W, 5% unless

otherwise noted.

1/4”
Stereo
Phone

Jack

Figure 9. Stereo Phone Jack Connections

+5 Volt

Signal Out

Ground

Schematic Model ME-9207B Free Fall Adapter (956-03527A)

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012-05760B Free Fall Adapter

Technical Support

Feedback

If you have any comments about the product or
manual, please let us know. If you have any sugges­tions on alternate experiments or find a problem in the
manual, please tell us. PASCO appreciates any cus­tomer
feedback. Your input helps us evaluate and improve
our product.

To Reach PASCO

For technical support, call us at 1-800-772-8700 (toll­free within the U.S.) or [phone].

fax: [phone]
e-mail: [e-mail]
web: www.pasco.com

Contacting Technical Support

Before you call the PASCO Technical Support staff, it
would be helpful to prepare the following informa­tion:

➤ If your problem is computer/software related, note:

 Title and revision date of software;
 Type of computer (make, model, speed);
 Type of external cables/peripherals.

➤ If your problem is with the PASCO apparatus,

note:

 Title and model number (usually listed on the

label);

 Approximate age of apparatus;
 A detailed description of the problem/sequence

of events (in case you can’t call PASCO right
away, you won’t lose valuable data);

 If possible, have the apparatus within reach when

calling to facilitate description of individual parts.

➤ If your problem relates to the instruction manual,

note:

 Part number and revision (listed by month and

year on the front cover);

 Have the manual at hand to discuss your

questions.

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