PASCO SA-9241 User Manual

Pulley Atwood’s Machine

®

ME-9450A Super Pulley

Connector Rod

Thumbscrew

Figure 1

Figure 2

SA-9241

Instruction Sheet

012-04152B

*012-04152*

Introduction

The PASCO Pulley Atwood’s Machine is based on a device cre­ated by the Reverend George Atwood in 1784 to help demon­strate the mysteries of acceleration and force. In an ideal
Atwood’s Machine, two unequal masses are attached to a flexi­ble, massless string which passes over a frictionless, massless
pulley. (Please see Figure 1 below). The unequal gravitational
forces acting on the two masses provide a constant force that
accelerates both masses. The heavier mass is accelerated down­ward and the lighter mass is accelerated upward.

PASCO scientific provides the Atwood’s Machine shown above.
Two ME-9450A Super Pulleys are mounted on a 6.3 centimeter
(2.5 in) long, 0.9 cm (0.375 in) diameter rod. The connecting rod
is easily mounted on standard lab rod clamps* (not included).
The PASCO Pulley Atwood’s Machine (SA-9241) can handle
masses up to a few kilograms.

Operation

The Atwood’s Machine can be used with a Photogate Head,
PASCO computer interface, and PASCO data aquisition software
to allow measurement of the motion of one of the pulleys.

A real Atwood’s Machine is not as simple as its ideal counterpart.
The string is not massless and the pulley is not frictionless. The
rotational inertia of the pulley also reduces the simplicity of the
ideal Atwood’s Machine.

By using two low friction pulleys at each end of a connecting rod,
the effects of friction and rotational inertia are effectively
reduced to a minimum.

800-772-8700 www.pasco.com

• Remove the Super Pulley from one end of the Connector
Rod.

• Put the threaded end of the Connector Rod through the slot
on the edge of the Photogate Head (see Figure 3).

• Re-connect the Super Pulley to the Connector Rod.

• Connect the Photogate Cable to the Photogate Head and plug
the cable into a digital channel of a PASCO computer inter­face. (Note: For a PASCO interface without digital channels,
use a PS-2159 Digital Adapter.)

®

Pulley Atwood’s Machine SA-9241

Figure 3

Connector

Rod

Super Pulley

Photogate

Head

Photogate

Cable

.

Use the data acquisition software to record the motion of a pulley
as the masses on the ends of the string move up and down. Ana­lyze a graph display of velocity versus time to determine the
acceleration.

Additional Equipment Recommended:

• Photogate Head, PASCO Model ME-9498A

• Mass and Hanger Set, PASCO Model ME-9348

• Base and Support Rod, PASCO Model ME-9355

• String, PASCO Model SE-8050

• Adjustable Angle Clamp, PASCO Model ME-8744

Technical Support

For assistance with any PASCO product, contact PASCO at:

Address: PASCO scientific

10101 Foothills Blvd.
Roseville, CA 95747-7100

Phone: [phone] (worldwide)

800-772-8700 (U.S.)

Fax: [phone]

Web: www.pasco.com

Email: [e-mail]

For more information about the Pulley Atwood’s Machine and
the latest revision of this Instruction Sheet, visit:

www.pasco.com/go?SA-9241

Limited Warranty For a description of the product warranty, see the
PASCO catalog.

Copyright The PASCO scientific 012-04152B Pulley Atwood’s Machine
Instruction Sheet is copyrighted with all rights reserved. Permission is

granted to non-profit educational institutions for reproduction of any part of
this manual, providing the reproductions are used only in their laboratories
and classrooms, and are not sold for profit. Reproduction under any other
circumstances, without the written consent of PASCO scientific, is prohib­ited.
Trademarks PASCO and PASCO scientific are trademarks or registered
trademarks of PASCO scientific, in the United States and/or in other coun­tries. All other brands, products, or service names are or may be trade­marks or service marks of, and are used to identify, products or services
of, their respective owners. For more information visit
www.pasco.com/legal.

• PASCO Computer Interface and Data Acquisition soft­ware*

*See the PASCO catalog or web site at www.pasco.com for more informa­tion.

NOTE: Illustrations are for reference only; appearance of your
PASCO Pulley Atwood's Machine may vary.

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