PASCO SE-9409 User Manual

Instruction Sheet
for the PASCO
Model SE-9409

012-04500C

1/91

$1.00

ELASTIC CORD

Introduction

Elastic or “Bungie” cord is a
most useful item in the physics
class. Just a few of the experi­ments and demonstrations for
which you can use it are described
below.

Additional Equipment
Recommended:

• Wave Driver, WA-9753 or
SF-9324

• Sonic Ranger, ME-9346 (Apple) or
ME-9381A (IBM)

• Mass and Hangers, ME-9348

Setup Procedure

➀ Horizontal waves, mechanically driven.

Secure both ends of a length of cord and use a mechani­cal driver, (PASCO Model WA-9753 for example) to
drive the cord. As one varies the frequency, the cord
will produce excellent wave patterns at the various
multiples of wavelengths. Change the tension and
examine its effects on the frequencies.

➁ Horizontal waves, driven by hand.

Secure one end of the cord and set up standing waves.
You will want low frequency waves for this, so use a
long length of cord and relatively low tension. You can
produce standing waves, or just give the cord a sharp
pulse and watch the pulse travel down the cord and
reflect back.

➂ Vertical waves may be performed in the same way as

horizontal waves.

two times its length and has the advan-

tage over springs that it is almost

impossible to over stretch.

➄ A safe Bungie cord jumper.

Bungie cord jumping has become

a popular sport. You can simulate it

in your class room by attaching a

length of the cord to the ceiling and a

mass (about 250 g is good) to the end.

Keep the length of the Bungie

cord to about 1/3 of the height
of the room. If the motion can

be kept primarily in the vertical

plane, one can monitor the results with a Sonic Ranger.

≈ Energy conversion.

Hang a mass from the cord, then pull the mass down
and release. The amplitude of each oscillation will be
less than the previous. By monitoring the decreases in
amplitude, the amount of energy lost per oscillation can
be calculated. The total energy of a particle in simple
harmonic motion is proportional to the square of the
amplitude of motion.

∆ Spring constant.

One can confirm Hooke’s law, the description of the
relationship between the force applied to a spring and its

stretched length (F
length of a piece of Bungie cord. Hang a known mass
from the end of the cord and measure the cord’s
stretched length. Determine the spring constant: “k” =
F/x (F = mg = force applied by the known mass; x = the
difference between the stretched and unstretched
length). Vary the amount of applied mass and measure
the corresponding amount of stretch. Plot applied force
versus amount of stretch.

= -kx). Measure the unstretched

net

√ A very long spring.

Use the cord instead of a spring for large demonstra­tions. Hang a mass, let it drop, and observe the period
of oscillation. Use a sonic ranging system (the PASCO
Sonic Ranger for example) to measure displacement as a
function of time. The Bungie cord will stretch about

10101 Foothills Blvd. • P.O. Box 619011 • Roseville, CA 95678-9011 USA

Phone [phone] • FAX [phone] • TWX 910-383-2040

➤ NOTE: To make the Bungie cord even
more visible, dye it with RIT fluorescent dye
or use a fluorescent “High Lite” type pen.

better

ways to

teach physics

Limited Warranty

012-04500C

PASCO scientific warrants this 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. This
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.

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