PASCO ME-6964 User Manual

Instruction Manual

PAStrack Wheel Set

ME-6964

012-10635A

Mounting

Screw

Low-friction Wheels

Introduction

Alignment Tabs

Low-friction Wheels

Mounting Screw

The PAStrack Wheel Set consists of two wheel enclosures that mount on the bottom of any PASCO PAStrack. Once the wheel set is mounted on the bottom of a PAStrack, the PAStrack with wheels can be used to help students better understand frames of reference. For example, a cart runs on top of the PAStrack with wheels as the PAStrack itself moves. Using visual observation or motion sensors, students can compare the motion of the cart relative to the moving PAStrack and relative to the “stationary” lab frame.

The PAStrack with wheels can be used on any flat surface such as a tabletop or floor. It can also be used with a PASCO dynamics track, which reduces friction and is easily leveled or inclined. The PAStrack with wheels is compatible with other PASCO carts, including motorized carts and fan carts.

Assembly

Each wheel enclosure has alignment tabs and a mounting screw. The alignment tabs are designed to fit into similarly shaped notches on both ends of the PAStrack approximately 11 cm from each end.

800-772-8700 www.pasco.com

Remove

Accessory

Screw

Align Tabs

with Notches

Mounting Screw

PAStrack with wheels Suggested Activities

Remove the accessory screw from the threaded hole on the underside of the P AS track between the notches. Align the tabs of the PAStrack Wheel Set with the notches, and tighten the mounting screw into the threaded hole to hold the wheel set in place against the bottom of the PAStrack.

Suggested Activities

The experiments and demonstrations described in this manual can be done with the P AS track with wheels and other equipment listed on page 2. T o add motion sensors to any of the activities, use the setup detailed in Activity 1: Relative Velocity.

Suggested Equipment Part Number

PAStrack with Wheels Any PAStrack plus the ME-6964 Stationary Track part of any PASCO dynamics system Dynamics Cart ME-6951, ME-6950, ME-9430, or ME-9454 Motorized Cart ME-9781 Time Pulse Accessory ME-9496 Fan Cart or Fan Accessory ME-9485 or ME-9491 Sail Part of ME-9485, or use a piece of cardboard Compact Cart Mass (250 g) ME-6755 or similar Rotational Inertia Set ME-9774 Motion Sensors (qty. 2) CI-6742 or PS-2103

Some of these activities also call for stands or blocks to position sensors and incline the track.

Activity 1: Relative Velocity

In this experiment, you will use two motion sensors to measure the velocities of the PAStrack with wheels and a motorized cart in the lab reference frame. From these measurements, you will calculate the velocity of the cart in the PAStrack with wheel’s reference frame.

Equipment Setup

1. Set up two motion sensors as pictured to measure the velocities of the motorized

cart and PAStrack with wheels

Note that the motion sensor is mounted to allow the PAS track with wheels to pass under it. The sensor’s position and angle are adjusted so it detects only the cart, not the PAStrack with wheels. (The support piece in the picture is the CI-6692

NOTE: The illustrations

show a PASCO Relative Motion Track in place of the PAS track with wheels. All of the setups and procedures are the same for the PAStrack with wheels.

Model No. ME-6964 Suggested Activities

Dynamics Track Mount; a similar arrangement can be achieved with a rod stand, right-angle clamp, and horizontal support rod.)

2. Plug the Time Pulse Accessory into the EXT. INPUT jack on the Motorized Cart.

3. Set the switch on the cart to ON (Batt.), and turn speed knob to maximum (f ull

clockwise).

4. Set the rotary switch on the Time Pulse Accessory to position 3, the variable-time

setting.

5. Place the cart at one end of the PAStrack with wheels and press the START but-

ton on the Time Pulse Accessory; after a two second delay the cart will drive for a few seconds and stop automatically. Adjust the variable-time knob so that the cart drives nearly the full length of the PAStrack with wheels without falling off the end. (It is not necessary to let the PAStrack with wheels move freely for this step.)

6. Set the sample rates of both sensors to 20 Hz. Record some trial data runs and

adjust the positions and angles of the sensors to get clear position and velocity data.

Calculations Setup

For more information about creating calculations in DataStudio, click the Calculate button, then press F1 (Windows) or the Help key (Mac).

1. Since the sensors are facing in opposite directions, it is necessary to

create a calculation that reverses the velocity measurement of the right-hand sensor; that way both sensors will register movement from left to right as positive. In DataStudio, create the calculation

= −V

track

where V is the measured velocity.

2. Create a second calculation for the velocity of the cart relative to the

PAStrack with wheels:

= V

cart

− V

track

where V

track

is the measurement made by the left-hand sensor and

cart

is the previous calculation.

rel

3. (This step is optional.) If you plan to use this arrangement of sensors for other

experiments in which you will compare the positions of the cart and PAStrack with wheels, create a calculation to transform the position measurement made by the right-hand sensor:

=0.5− x

where x

measured

track

is the measurement made directly by the right-hand

measured

sensor. The number 0.5 is the difference (in meters) between the length of the PAStrack with wheels and the distance between the sensors, which may be different in your setup. This calculation will make the readings from both sensor identical when the back of the cart is even with the left end of the PAStrack with wheels.

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