Position Match Graph

Materials

PASPORT Xplorer GLX (PS-2002)

PASPORT Motion Sensor (PS-2103)

Purpose:

The purpose of this activity is to explore graphs of motion (position vs. time) using a motion sensor to measure your motion as you move back-and-forth along a straight line at different speeds.

Background:

When describing the motion of an object, knowing where it is relative to a reference point, how fast and in what direction it is moving, and how it is accelerating (changing its rate of motion) is essential. A sonar ranging device such as the PASPORT Motion Sensor uses pulses of ultrasound that reflect from an object to determine the position of the object.

As the object moves, the change in its position is measured many times each second. The change in position from moment to moment is expressed as a velocity (meters per second). The change in velocity from moment to moment is expressed as an acceleration (meters per second per second). The position of an object at a particular time can be plotted on a graph. A graph is a mathematical picture of the motion of an object. For this reason, it is important to understand how to interpret a graph of position versus time. In this activity you will plot a graph of your motion in real-time, that is, as the motion is happening.

Procedure:

Part 1 – Practice Round

  1. Turn on the GLX
  2. Connect the Motion Sensor to one of the sensor ports on the top end of the GLX.
  3. Put the range selection switch on the Motion Sensor to the “far” (Person) setting.
  4. Place the motion sensor on the table or another flat surface. Aim the sensor (using the dial on the side) towards the person who is going to do the walking.
  5. Create a graph
  6. Pick a person to do the walking (either towards or away from the sensor).
  7. When the walker is ready, have another person hit the Start/play button on the sensor and walk either towards or away from the motion sensor.
  8. When the person is done walking, hit the Start/play button again to stop taking data.
  9. ANALYSIS Q1 – What is the slope of the graph you produced? What was the velocity of the person walking?
  10. Create a graph that has a slope of +1/2. (follow steps a-c from above)

ANALYSIS Q2 – What was the velocity of the person walking this time? What does the negative sign indicate about the velocity of the walker?

  1. Create a graph with zero slop.

ANALYSIS Q3 – Describe the motion of the walker to produce a graph with zero slop.

TURN OVER

Part 2 - Challenge Graph:

  1. To open the Challenge Graph hit the “home” button (looks like a house)
  2. In the Home Screen, select Data Files and press “Check.”
  3. In the Data Files Screen, use the cursor keys (arrows) to navigate to the “position match” file. Press “F1” to open the file. It may take a few moments to open the file.
  4. Once the file is open press the “home” button to return to the Home Screen.
  5. Press F1 to open the Graph screen.
  6. The Graph Screen should show a “target” graph. It is up for your team to match the target graph.
  7. Using the GLX like before, try to match the graph.
  8. Analysis of your match:
  9. After a trial, press “F4” to open the menu and select “Graph 2.” Press “Check” to activate your choice.
  10. The error graph will give a score in units of m*s. The lower the score, the better you were at matching the graph of position vs time.
  11. Press the “F4” button and select “Graph 1” to return to the original graph. Press “check” to activate your choice.
  12. In Graph 1, press “check” to activate the vertical axis menu. Use the arrow buttons to select the “Run Number” menu and press “check” to open the menu. Select the run number and delete the data run.
  13. Repeat the previous steps several times to improve (hopefully) your score.
  14. ANALYSIS Q4 – What was your best/lowest Graph Match score?
  15. ANALYSIS Q5 – Sketch a Velocity vs. Time graph from the given position-match graph. (Remember units)