Kinematics Lab Activity

Measuring Average Speed

The purpose of this activity is to give you practice in measuring average speeds, and to get you thinking about average and instantaneous speeds.

This activity has two parts. First, you will calculate some average speeds. Then, you will use these calculated average speeds to determine an unknown distance.

**Important:** You will be working in a group of 3-4
students, but **this is not a group activity**. You will
collect your own data, and make your own calculations. Each student
will submit their own results and conclusions.

meter stick |
stop watch |

1. You need to decide on an "event" for the students in your group
to participate in. This event could be walking, running, walking
backwards, walking heel-to-toe, hop, skip, crawl, whatever
(**HINT:** The other students in your group will be
planning an event for *YOU*, too...)

2. It is your job to determine the average speed for each student in your group for your event. Think about what you need to measure to determine the average speed, and how you will go about making the calculations. Then construct a data table to record your data and display your results. Be sure to label the columns and indicate the units of measurement for each quantity. You should allow for 2 to 3 trials for each person in your event.

3. Supervise your event, and record your data. Each person in your
group (except you) will "run" in your event, and you will participate
in the event of every other person in your group.

1. It is more important to move at a consistent (and
**safe**) speed than it is to go fast. There are no
prizes for *"winning"* these events!

2. If a person in your group suggests an activity that you think
is unsafe, degrading, or will get your clothes dirty, **you
have the right to insist that they pick some other "event"**.
The teacher will settle any disagreements that cannot be settled
among the participants.

When you have finished Part 1, report to your teacher. It is not necessary that your calculations be complete.

1. Your teacher will show you an "unknown distance". Time your participants in your event over this distance. Record the results in a data table.

2. Use your average speed calculation from Part 1 and the time required to cover the "unknown distance" to calculate the "unknown distance". Put your results in the data table.

3. Measure (and record) your "unknown distance" with a meter stick, so you can judge the accuracy of your calculation in number 2.

1. How do your measured and calculated values for the "unknown distance" compare? If there is a large discrepancy, why do you think it occurred?

2. How is the average speed of a person related to the total distance covered and the total time taken?

3. If the average speed of a person was 1.2 meters/second, does
this mean that their speed was exactly 1.2 meters/second the whole
time? Is the average speed related to the maximum or minimum speed of
the person? Explain why you think so.

last update December 9, 1996 by JL Stanbrough