PASCO ME-9847 User manual

®
Instruction Sheet
012-12002A
PASCO Rotational Inertia Wands
ME-9847
*012-12002*
Introduction
The ME-9847 PASCO Rotational Inertia Wands are designed to show how the distribution of mass in an object
determines the object’s rotationa inertia (moment of inertia). The blue inertia wand has masses installed at both
ends of the tube. The red inertia wand has masses installed near the grip at the center of the wand. Both wands
have the same amount of mass, so they weigh the same and “feel” equally heavy when lifted.
Theory
Objects that can rotate have a tendency to resist any change in their rotation. If they are at rest, they tend to stay
at rest. If they are in motion (rotating), they tend to stay in motion. This tendency is called rotational inertia (or
moment of inertia). If a net torque (twisting force) is applied to an object that can rotate, it will change the rota-
tion of the object. The amount of change in the rotation (called the angular acceleration, ) is directly propor-
tional to the net torque, , and inversely proportional to the rotational inertia, I.
The rotational inertia depends on the amount of mass in the object and the distribution of mass. If the mass of an
object is close to its center of rotation, the rotational inertia will be smaller. It will be ‘easier’ to start rotating and
stop rotating the object. If the mass is distributed far away from the object’s center of rotation, the rotational iner-
tia will be larger. It will be ‘harder’ to start rotating and stop rotating the object.
Included Equipment
Rotational Inertia Wand, Blue
Rotational Inertia Wand, Red
Grip area
Grip area

I
--=

®
PASCO Rotational Inertia Wands Operation
2
Operation
1. Grasp the grip area of one of the rotational inertia wands. Hold the wand so that it
is vertical or horizontal.
2. Twist your wrist to rotate the wand back and forth. Make a note of how hard or
how easy it is to rotate the wand.
3. Repeat with the other wand. Again make a note of how hard or how easy it is to
rotate the wand.
How does the blue wand (with the masses farther from the grip area) compare to the
red wand (with the masses nearer the grip area of the wand)?
Technical Support
For assistance with any PASCO product, contact PASCO at:
Limited Warranty
For a description of the product warranty, see the PASCO catalog.
Copyright
The PASCO scientific 012-12002A PASCO Rotational Inertia Wands Instruction Sheet is copyrighted with all rights reserved. Permis-
sion 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, PASCO scientific, DataStudio, PASPORT, Xplorer, and Xplorer GLX are trademarks or registered trademarks of PASCO sci-
entific, in the United States and/or in other countries. For more information visit www.pasco.com/legal. Windows is a registered trade-
mark of Microsoft Corporation in the United States and/or other countries. Mac is a trademark of Apple Computer, Inc., registered in
the U.S. and other countries.
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: [email protected]