LAB 1
Team Building & Motion Diagrams
OBJECTIVES
1. To start forming effective small working groups for the class.
2. Use the Motion Sensor to measure and plot your position and velocity as you move in a
straight line at different speeds.
3. Understand the concept of position, velocity, and acceleration.
4. Try and match position vs. time and velocity vs. time graphs
EQUIPMENT
Pasco 850 Universal Interface, motion sensor, support rod, moving object (you)
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 is essential. A sonar ranging
device such as the PASCO Motion Sensor uses pulses of ultrasound that reflect from an object
and determine the position, velocity, and acceleration of the object. From this data, one can
create graphs of (x, v, a) vs. t and interpret the motion of the object versus time. In this activity
you will plot a graph of position and velocity in real-time and determine from these graphs, how
this object is moving.
PROCEDURE
Part 1: Team Building
Please follow the instructor’s instructions for this activity.
Part 2: Position vs. Time
Use the Motion Sensor to measure your body’s position as you move in a straight line at
different speeds. Use Capstone to plot your motion on a graph of position and time. The
challenge is to move in such a way that a plot of your motion on the same graph will “match” the
line that is already there. This activity is easier to do if you have a partner run the computer
while you move.
a. Setup a Motion Sensor so that it is aimed at your midsection when you are standing in front
of the sensor and connect it to the PASCO interface. Make sure that you can move at least
2 meters away from the Motion Sensor. Position the computer monitor so you can see the
screen while you move away from the Motion Sensor.
b. Open up the Motion Diagrams Lab activity and click on the Position vs. Time tab. The
graph will plot your position (m) vs. time (s).
c. Experiment with the motion sensor. Move forwards and backwards at different speeds. Try
and move at a constant velocity and at a constant acceleration. Notice the shape of the
position vs. time plots as you perform different motions.
d. Study the plot of one of the three different Position Games. Sketch the plot and from this
plot (i) draw a motion diagram and (ii) describe in words the motion represented by
the graph (i.e. standing still at x = 1.0 m for 1.5 seconds, moving forward at 1.5 m/s for 2.0
seconds, …).
e. Have one of your lab partners stand in front of the Motion Sensor. When everything is ready,
start recording data. There is a countdown before data recording begins.
f.
Watch the plot of your motion on the graph and try to move so the plot of your motion
matches the Position versus Time plot already there. Determine how well your plot of motion
matches the plot that was already in the graph by examining the “Score” calculation. Repeat
the data recording process a second time. Try to improve the match between the plot of
your motion and the plot that is already on the graph.
g. Have each member of your group try and reproduce the graph using the motion detector.
Part 3: Velocity vs. Time
Use the Motion Sensor to measure your velocity rather than your position. Again, the challenge
is to move in such a way that a plot of your motion on the same graph will “match” the line that
is already there. You will find that matching the velocity graph is significantly more difficult than
matching the position graph.
a. Click on the Velocity vs. Time tab. The graph will plot your velocity (m/s) vs. time (s).
b. Experiment with the motion sensor. Move forwards and backwards at different speeds.
Stand still. Try and move at a constant velocity and at a constant acceleration. Notice the
shape of the velocity vs. time plots as you perform different motions.
c. Study the plot of one of the four different Velocity Games. Sketch the plot and from this
plot (i) draw a motion diagram and (ii) describe in words the motion represented by
the graph (i.e. moving forward at 0.75 m/s for 1.5 seconds, accelerating at 1.0 m/s2 for 2.0
seconds, …).
d. When everything is ready, start recording data. Watch the plot of your motion on the Graph,
and try to move so that the plot of your motion matches the Velocity versus Time plot that is
already there.
e. Repeat the data recording process a second time to try and improve the match between the
plot of your motion and the plot that is already on the graph. Have each member of your
group try and reproduce the graph using the motion detector.
Part 4: Matching Position vs. Time and Velocity vs. Time Graphs
Use a motion sensor and equipment available in the physics lab to try and reproduce different
position vs. time and velocity vs. time graphs.
a. Study each of the six graphs below and discuss with your lab partners what kind of motion
the graph represents. Then discuss different ways you might reproduce the motion using
equipment that we have available in the physics lab.
b. Using the motion sensor and any equipment available, try and reproduce each graph.
c. For each graph, (i) sketch the graph, (ii) draw a motion diagram, (iii) describe the
motion it represents, and (iv) describe what you did to reproduce the motion.