Pasco Scientific ME-9435A, ME-9429A, ME-9452, ME-9458 Instruction Manual And Experiment Manual

Includes

Teacher's Notes

and

Typical

Experiment Results

Instruction Manual and
Experiment Guide for the

012-05035E

PASCO scientific Model
ME-9435A and ME-9429A

Dynamics Cart Accessory

Track Set (1.2m version)

Model

ME-9435

DYNAMICS

TRACK

7/94

CAUTION

MAGNET

AVOID CONTACT WITH COMPUTERS

© 1992 PASCO scientific $10.00

012-05035E Dynamics Cart Accessory Track Set

Table of Contents

Section Page

Copyright, Warranty, and Equipment Return................................................... ii

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

Equipment......................................................................................................... 2

Assembly .......................................................................................................... 3

Using the Friction Block................................................................................... 4

Replacement Parts ............................................................................................ 5

Experiments

Exp 1: Conservation of Momentum in Explosions .............................. 7

Exp 2: Conservation of Momentum in Collisions ................................ 9

Exp 3: Simple Harmonic Oscillator.................................................... 11

Exp 4: Oscillations on an Incline........................................................ 15

Exp 5: Springs in Series and Parallel.................................................. 19

Exp 6: Newton's Second Law ............................................................. 22

Exp 7: Newton's Second Law II ......................................................... 23

Exp 8: Acceleration down an Incline ................................................. 25

Exp 9: Conservation of Energy .......................................................... 29

Additional Experiments .................................................................................. 33

Teacher’s Guide.............................................................................................. 35

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

i

Dynamics Cart Accessory Track Set 012-05035E

Copyright, Warranty and Equipment Return

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

Copyright Notice

The PASCO scientific Model ME-9435A Dynamics
Cart Accessory Track Set manual is copyrighted and all
rights reserved. However, permission is granted to non­profit educational institutions for reproduction of any part
of this 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 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.

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.

NOTE: NO EQUIPMENT WILL BE

ACCEPTED FOR RETURN WITHOUT AN
AUTHORIZATION FROM PASCO.

When returning equipment 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:

➀ The packing carton must be strong enough for the

item shipped.

➁ Make certain there are at least two inches of

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

➂ Make certain that the packing material cannot shift

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

Credits

This manual authored by: Ann & John Hanks

Teacher’s guide written by: Eric Ayars

Address: PASCO scientific

10101 Foothills Blvd.
Roseville, CA 95747-7100

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

ii

012-05035E Dynamics Cart Accessory Track Set

Introduction

The PASCO Model ME-9435A Dynamics Cart Acces­sory Track Set enables the user to perform a wide vari­ety of experiments when used with the Dynamics Cart
(ME-9430) and the Collision Cart (ME-9454). The
Track ensures easy setup and accurate alignment with
the lowest possible friction, and it accomodates most
linear motion experiments.

Features include:

•Length is adequate for standard experiments and
limited lab and table space.

•Low friction wheel slots keep the carts aligned
even after a collision.

•Mounted to a standard lab rod, the track adjusts to
any angle for inclined plane experiments.

•Durable construction with built-in End Stop to
protect the cart.

•Adjustable End Stop allows the use of any length
of track

1

Dynamics Cart Accessory Track Set 012-05035E

Equipment

The ME-9435A Dynamics Cart Accessory Track Set
includes the following:

• Dynamics Cart Track:

1.2m extruded aluminum track with alignment
grooves in top surface, leveling foot and bumper
block.

➤ NOTE: The bumper block has a round head
screw on the top to allow easy attachment of
springs, string, etc.

•Adjustable End Stop

•Super Pulley with Clamp.

•(3) Springs for simple harmonic motion with stor­age tubes.

➤ NOTE: A small piece of double sided tape is

attached to the ends of each storage tube so the
tubes may be permanently attached to the under­side of the Dynamics Cart Track.

•Friction Block

•Magnet Bumper Kit (includes 2 magnets) with
storage tube.

Additional Equipment Required for ME-9458

• Dynamics Cart with Mass (ME-9430)

Specific experiment requirements:

– Thread

– Mass Set

– Super Pulley with Clamp

– Base and Support Rod

– Metric Ruler

– Stopwatch

– Mass balance

– Wooden or metal block

– Graph paper

Additional Equipment Recommended

•Photogate Accessory Kit with Software, (Apple)
(ME-9436) or (IBM PC) (ME-9437)

or

•Software Accessory Kit, (Apple) (ME-9438) or
(IBM PC) (ME-9439).

•Pivot Clamp [for use with the Base and Support
Rod (ME-9355)].

•Label: "CAUTION! MAGNET".

Super Pulley

with Clamp

"CAUTION! MAGNET"

label

CAUTION

ACT WITH COMPUTERS

MAGNET

AVOID CONT

Dynamics Cart Track

Magnet Bumper Kit

with storage tube

Springs with

Storage tubes

Pivot Clamp

Adjustable

End Stop

2

End Stop with

Bumper and Leveling

Foot

Model

ME-9435

DYNAMICS

TRACK

Friction Block

012-05035E Dynamics Cart Accessory Track Set

Assembly

Thread forming

Magnet Bumper

Assemblies

Dynamics Cart

(not included)

screws

Plunger Bar

Front End Cap

Hook-and-pile

Pads

Installing the Magnet Bumpers

➤ NOTE: The ME-9454 Collision Cart comes
with 2 sets of magnetic bumpers already in­stalled. The ME-9430 Dynamics Cart comes
without any magnetic bumpers.

➀ Detach the end cap at the rear of the cart by remov-

ing the two screws from the rear end cap as shown.

➤ NOTE: The screws that secure the end caps
to either end of the Dynamics Cart are thread
forming screws and may require substantial force
to remove and reinstall. A #1 Phillips point
screw driver is required.

Rear End Cap

➤ Note: This end cap does
not have the hook and pile
pads

Installing the Pivot Clamp

➀ Remove Pivot Clamp Assembly from underneath

the Dynamics Cart Track.

➁ Insert long thumb screw through the hole in the

Pivot Clamp Block and thread
hex nut.

➤ NOTE: Observe the orientation of the Pivot
Clamp Block. Also note that the flat side of the
square nut must face the outside of the Dynamics
Cart Track as shown.

1

⁄2 to 3⁄4 turn into the

➁ Insert the two magnet bumper assemblies, magnet

end first, into the cavities on the inside of the end
cap as shown.

➤ CAUTION!

Each magnet assembly consists of a foam pad
attached to a neodymium magnet. The neody-
mium magnets are extremely strong. Though
only the south end of the magnet is exposed they
can still be a hazard. When opposite poles are
brought close to each other they will accelerate
rapidly and can pinch fingers or be easily
chipped. They can also erase computer disks and
distort computer monitors and television sets.

➂ Replace the rear end cap with the two screws.

Dynamics Cart Track

Pivot Clamp Block

Short Thumb

Square Nut

Bracket Washer

Long Thumb

Screw

Screw

➂ Align the square nut within the groove on the de-

sired side of the Dynamics Cart Track. Locate and
adjust Pivot Clamp to desired position and tighten
thumb screw to secure.

3

Dynamics Cart Accessory Track Set 012-05035E

Installing the Adjustable End Stop

The Adjustable End Stop can be used at any point on
the track as a bumper. Either the plunger bar on the
cart or the cart's magnetic bumper can be used to
rebound off the End Stop because the End Stop
contains magnets. The cart can also be stopped against
the End Stop when the velcro end of the cart hits the
velcro side of the End Stop. This is useful when it is
desired to keep the cart from rebounding. There is also
a post on top of the End Stop to allow a string or
spring to be attached. Assembly is as follows:

➀ The Adjustable End Stop Assembly consists of the

End Stop with two magnets installed, a black plas­tic thumb screw, and a square nut.

➁ If photogate brackets are to be used, it is best to in-

stall the End Stops in the groove opposite to the
side being used for photogates so the End Stop can
slide past the photogates without interference.

➂ Align the square nut within the groove on the de-

sired side of the Dynamics Cart Track as shown.
Locate and adjust the End Stop to the desired posi­tion and tighten the thumb screw to secure.

➃ When storing the End Stop when it is not on the

track, remember that it has two strong magnets in
it. Keep the End Stop away from computers.

Attaching Adjustable End-Stop to Track

Using the Friction Block

The Friction Block is a wood rect­angle that fits neatly on top of the
Dynamics Cart (ME-9430).

In experiments that use the Friction Block you will
investigate some of the properties of sliding friction ­the force that resists the sliding motion of two objects
when they are already in motion.

The top and bottom surfaces of the Friction
Block have a slot which allows a “picket
fence” to be inserted. (See the
PASCO catalog.) An eye
screw is provided so
that you may easily
attach a string to
the block.

The exposed wood on the top and one side of the block
produce minimal friction. Felt pads attached to the
bottom surface and the other side provide more
friction. Mass can be placed on the top surface of the
Friction Block as shown.

4

012-05035E Dynamics Cart Accessory Track Set

Replacement Parts (ME-9435A)

Description Part No.

Magnet Bumper Kit Assembly (2per) 003-05027

Super Pulley with Clamp (1ea) ME-9448A

Friction Block (1ea) 003-04708

Label, Magnet Caution (1ea) 646-04445

Spring (3ea) 632-04978

Pivot Clamp Assembly: 003-05019

Pivot clamp (1ea) 648-04654

Long thumb screw (1ea) 610-183 & 620-047

Short thumb screw (1ea) 610-181 & 620-067

Washer 615-184

Square nut (1ea) 614-054

Adjustable End Stop (1ea) 003-04989

Fixed End Stop (1ea) 003-05018

5

Dynamics Cart Accessory Track Set 012-05035E

Notes:

6

012-05035E Dynamics Cart Accessory Track Set

p

Δ

Experiment 1: Conservation of Momentum in Explosions

EQUIPMENT NEEDED:

– Dynamic Cart with Mass (ME-9430)
– Collision Cart (ME-9454)
– Dynamics Cart Track
– Meter stick
– Mass balance

Purpose

The purpose of this experiment is to demonstrate conservation of momentum for two carts
pushing away from each other.

Theory

When two carts push away from each other and no net force exists, the total momentum of
both carts is conserved. Because the system is initially at rest, the final momentum of the
two carts must be equal in magnitude and opposite in direction so the resulting total mo­mentum of the system is still zero.

Therefore, the ratio of the final speeds of the carts is equal to the ratio of the masses of the
carts.

To simplify this experiment, the starting point for the carts at rest is chosen so that the two
carts will reach the end of the track simultaneously. The speed, which is the distance
divided by the time, can be determined by measuring the distance traveled since the time
traveled by each cart is the same.

Thus the ratio of the distances is equal to the ratio of the masses:

Procedure

= m1v1– m2v2=0

v

m

1

2

=

v

m

2

2

x

1

v

1

=

v

Δx

2

Δ

x

Δ

x

Δt

1

2

Δx

1

=

Δx

2

=

2

m

2

m

1

➀ Level the track by setting a cart on the track to see which way it rolls. Adjust the leveling

feet to raise or lower the ends until a cart placed at rest on the track will not move.

7

Leveling foot

Dynamics Cart Accessory Track Set 012-05035E

➁ For each of the following cases, place the two carts against each other with the plunger of the

Dynamics Cart pushed completely in and latched in its maximum position (see Figure 1.1).

➂ Push the plunger release button with a short stick and watch the two carts move to the ends of

the track. Experiment with different starting positions until the two carts reach their respective
ends of the track at the same time. Then weigh the two carts and record the masses and the
starting position in Table 1.1.

CASE 1: CARTS OF EQUAL MASS (Use two carts without any additional mass bars)

CASE 2: CARTS OF UNEQUAL MASS (Put one mass bar in one cart, none in the other)

CASE 3: CARTS OF UNEQUAL MASS (Put two mass bars in one cart, none in the other)

CASE 4: CARTS OF UNEQUAL MASS (Put two mass bars in one cart, one mass bar in

the other)

Table 1.1

Mass 1 Mass 2 Position x

1

x

2

x1/x

2

Data Analysis

➀ For each of the cases, calculate the distances traveled from the starting position to the end of

the track. Record the result in Table 1.1.

➁ Calculate the ratio of the distances traveled and record in the table.

➂ Calculate the ratio of the masses and record in the table.

Questions

➀ Does the ratio of the distances equal the ratio of the masses in each of the cases? In other

words, is momentum conserved?

➁ When carts of unequal masses push away from each other, which cart has more momentum?

m2/m

1

➂ When the carts of unequal masses push away from each other, which cart has more kinetic

energy?

➃ Is the starting position dependent on which cart has its plunger cocked? Why?

8

012-05035E Dynamics Cart Accessory Track Set

p

Experiment 2: Conservation of Momentum in Collisions

EQUIPMENT NEEDED:

– Dynamics Cart with Mass (ME-9430)
– Collision Cart (ME-9454)
– (2) Bumper magnet set (installed)
– Dynamics Cart Track
– Paper

Purpose

The purpose of this experiment is to qualitatively explore conservation of momentum for elastic and
inelastic collisions.

Theory

When two carts collide with each other, the total momentum
regardless of the type of collision. An elastic collision is one in which the two carts bounce off each

other with no loss of kinetic energy. In this experiment, magnetic bumpers are used to minimize the
energy losses due to friction during the collision. In reality, this “elastic” collision is slightly inelastic.
A completely inelastic collision is one in which the two carts hit and stick to each other. In this
experiment, this is accomplished with the hook-and-pile tabs on the end caps of the carts.

of both carts is conserved

= mv

Procedure

➀ Level the track by setting a cart on the track to see which way it rolls. Adjust the leveling feet at the

end of the track to raise or lower that end until a cart placed at rest on the track will not move.

➁ Draw two diagrams (one for before the collision and one for after the collision) for each of the

following cases. In each diagram, show a velocity vector for each cart with a length that approxi­mately represents the relative speed of the cart.

Part I:Elastic Collisions

A. Carts with Equal Mass

Orient the two carts so their magnetic bumpers are toward each other.

Case 1: Place one cart at rest in the middle of the track. Give the other cart an initial velocity toward the

cart at rest.

Case 2: Start the carts with one at each end of the track. Give each cart approximately the same velocity

toward each other.

Case 3: Start both carts at one end of the track. Give the first cart a slow velocity and the second cart a

faster velocity so that the second cart catches the first cart.

Leveling foot

9

Dynamics Cart Accessory Track Set 012-05035E

B. Carts with Unequal Mass

Put two mass bars in one of the carts so that the mass of one cart is approximately three times
the mass (3M) of the other cart (1M).

Case 1: Place the 3M cart at rest in the middle of the track. Give the other cart an initial

velocity toward the cart at rest.

Case 2: Place the 1M cart at rest in the middle of the track. Give the 3M cart an initial velocity

toward the cart at rest.

Case 3: Start the carts with one at each end of the track. Give each cart approximately the

same velocity toward each other.

Case 4: Start both carts at one end of the track. Give the first cart a slow velocity and the

second cart a faster velocity so that the second cart catches the first cart. Do this for
both cases: with the 1M cart first and then for the 3M cart first.

Part II: Completely Inelastic Collisions:

➂ Orient the two carts so their hook-and-pile ends are toward each other. Make sure the

plunger bar is pushed in completely so it won't interfere with the collision.

➃ Repeat the same procedures listed in Part I for carts with equal mass and carts with un-

equal mass.

Questions

➀ When two carts having the same mass and the same speed collide and stick together, they

stop. What happened to each cart’s momentum? Is momentum conserved?

➁ When two carts having the same mass and the same speed collide and bounce off of each

other elastically, what is the final total momentum of the carts?

10