PASCO ME-9341 INTRODUCTORY ROTATIONAL APPARATUS - Manual (Page 5)

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012-03051F Introductory Rotational Apparatus
Introduction
➤
NOTE: The original 3-hole Smart Pulley has been
replaced . The new PASCO Smart Pulley has 10
spokes and less friction than the 3-hole pulley. If you
currently have 3-hole pulleys and wish to replace
them with 10-spoke pulleys an upgrade kit is avail-
able from PASCO. The upgrade kit includes software
that allows use of either the 3-hole or 10-spoke
pulleys. This manual makes reference to both pulleys.
With the PASCO ME-9341 Introductory Rotational
Apparatus, your students can perform a variety of
experiments in rotational mechanics, including investi-
gations into torque, angular acceleration, moment of
inertia, and conservation of angular momentum.
Setup is quick and operation is simple. As shown in
Figure 1, a platter spins on low-friction ball bearing
supports. Torques can be applied to the platter with
various torque arms and forces, and the angular
velocity of the platter can be monitored over time to
determine angular acceleration. The moment of inertia
of the rotating system can be varied by adding a
second platter, a steel ring, or a steel block.
The motion of the platter is described mathematically
by Newton's Second Law in its rotational form: t = Ia,
where t is the applied torque, I is the moment of inertia
of the spinning platter, and a is the angular accelera-
tion of the platter.
τ =
r x F
= Ια
r
F
Smart Pulley with photogate
(not included)
Figure 1 Rotational Diagram
Timing the Rotational Motion
A variety of timing systems can be used to measure the
motion of the Introductory Rotational Apparatus. The
most versatile option is the PASCO Smart Pulley.
However, standard photogate timers such as the PASCO
model ME-9206A or ME-9215A can also be used.
Timing with the Smart Pulley
The Smart Pulley (see Figure 1) connects to your
Apple II computer (II+, IIe, IIc, or IIGS), or IBM PC
or compatible, providing automatic data collection,
analysis, and graphing. As the platter spins, the pulley
is held lightly against the rim of the platter, and
therefore spins with the platter. The Smart Pulley
photogate monitors the rotation of the pulley, sending
its signals to the computer for timing and analysis.
The software for the Smart Pulley includes options
designed specifically for use with the Introductory
Rotational Apparatus, producing tables and graphs
showing angular displacement, velocity, and accelera-
tion as a function of time.
The Smart Pulley is more than just a computer timer
for the Rotational Apparatus. When used with an
Apple II or IBM PC computer and standard laboratory
equipment such as an air track or dynamics carts, the
Smart Pulley provides a complete introductory lab in
linear mechanics. See the PASCO catalog for more
information about the Smart Pulley System, or Smart
Pulley Timer and Accessories.
➤ IMPORTANT: If you are using the Smart
Pulley to time the motion of the Rotational
Apparatus, you should begin by familiarizing
yourself with the setup and operation of the
Smart Pulley. See the Smart Pulley manual and
the Smart Pulley Timer Software Manual.
Timing with a Standard Photogate
Timing for the Rotational Apparatus can also be
performed using a standard photogate timer, such as
PASCO model ME-9206A or ME-9215A. The five
ready-to-use experiments in this manual assume you
are using the Smart Pulley to time your experiments
with the Rotational Apparatus. However, each of
these experiments can be modified for standard
photogate timing. See the section, "Timing with a
Photogate." For more information about photogate
timers, see the current PASCO catalog.