0 Meet Me Where by ux10jsb


									                                Meet Me Where?

Suppose two people walking meet on the street and pass each other. These
motions can be modeled graphically. The motion graphs are linear if each
person is walking at a constant rate.

In this activity, you will investigate modeling the motion of these two people
to find where they will meet and at what rate each was walking.

For each group you will need:

     2 CBR units
     2 TI-83/84 Family Graphing Calculators

Each group should be made up of 2 walkers and 2 holders.


  1. Find the EasyData program on the calculators (Under Apps).
  2. Enter the setup instructions on both calculators.
      a.     Select the soft key Setup
      b.     Select the first option, 1: Dist. Then press         .
      c.     Once in the Sensor Setup screen, change the units to ft, by pressing the
             soft key Units        . Then press             . Then soft key OK
      d.     Select the soft key Start
      e.     Select the soft key OK         . This will start the data collection (Refer to

             running the experiment). The walker needs to start walking when the

             CBR2 starts fast ticking. The ticking will stop automatically after 5

Running the experiment

Both holders should stand at one end of the “course.” Walker A needs to start on the same end at the
holders and Walker B should be about 12 feet away facing the holders and Walker A.

Holder 1         Walker A 

Holder 2                                                        Walker B

Data Collection

1. The graph for Walker A should be a line with positive slope. The result for Walker B should be
   a line with negative slope. If you are not satisfied with the results of your experiment, select
   soft key Main           and try again.

2. When you are satisfied with you data, sketch a Distance-Time plot for each walker. The graph
   will appear on the screen.

3. You will need both sets of data to answer the following questions.

     1. Use            to determine the coordinates of the starting distance for

           each walker as Point 1. Using           trace to one other point on each of the

           distance graphs for each walker. Record this point as Point 2.

                               Point 1                                 Point 2

                       Time              Distance             Time               Distance

Walker A

Walker B

  2. The velocity of each walker is the change in distance, y , divided by the change

     in time, t . Find the velocity for each walker.

                                                                           y y2  y1
                    y  y2  y1         t  t2  t1         velocity =      
                                                                           t   t2  t1

Walker A

Walker B

  3. What are the units associated with the velocity? __________________________

  4. Slope is defined to be the rate of change. What would determine the rate of

     change of the distance for each walker?


  5. Find the slope and the y-intercept of each line. Write the equation of the line that best fits the

     Distance-Time graph for each walker.

                         m                    b                   Equation of Line

Walker A

Walker B
6. What is the physical significance of the y-intercept for each walker?



7. The slope of the line for Walker A is positive, while the slope of the line for Walker B is
negative. Explain the significance of the sign of each walker’s slope.




8. Press WINDOW. Change the Xmin to 0 and the Xmax to 5
   Ymin to 0 and the Ymax to 15. Press Y=. Enter the equation
   of the line for Walker A in Y1. Enter the equation for Walker
   B in Y2. Press GRAPH.Record a sketch of the graphs of the
   two walkers.

9. To find the point of intersection, press CALC (2nd [Trace]). Select 5:INTERSECT. Press
   ENTER ENTER ENTER. Record this point.

   Point of Intersection: _____________________________

10. What is the significance of the y-coordinate of the point of intersection of these two graphs?



11. What is the significance of the x-coordinate of the point of intersection of these two graphs?



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