Richard J. Watson - Orr High School       

Linear Motion: Speed, Velocity & Acceleration

Richard J. Watson              Orr High School       
                               730 North Pulaski Road              
                               CHICAGO IL 60624               
                               (773) 534-6500

Objectives:

This lesson is designed for high school and is adaptable to lower levels.
Students will be able to measure linear distance and time and calculate 
   velocity. 
Students will be able to plot graphs to show:  speed vs distance; 
                                               velocity vs distance                   

Materials Needed:

  2 meter sticks per group of 6 students
  2 stop watches or watches with second hands per group   
  1 Pencil and data sheet per group

Strategy 1:

Group students in groups of six:
   2 students - Using meter sticks in a leap frog manner students will
                measure distance of 100 meters from teacher designated spot. 
   1 student  - Stand at the starting position (designated by teacher) and 
                indicate the vehicle being timed by yelling "GO", or waving
                arms or flag, as it crosses the designated position. 
   1 student -  Stand at the finish position (100m from start) and  
                indicate the end of timing by yelling "STOP", or waving arms 
                or flag as the vehicle crosses the finish position.
   1 student -  Stand, with a stop watch or watch with a second hand, in view
                of the student indicating the beginning and the student
                indicating the ending of timing.
                At the "GO" command the student starts timing and at the "STOP"
                command student ends timing.
   1 student -  Record the time and direction of each vehicle on the data 
                sheet.  
                Obtain data from each of the other groups.
   Each group - Collect data for at least 3 vehicles

Strategy 2:
  
   5 students stand at the following positions, one student at each position:
     Start position - indicate the vehicle being timed by yelling "GO", 
                      waving arm or flag as it crosses the start position.
     25 meters position - begin timing at the "Start" command and stop timing
                      as vehicle crosses the 25 meter position.
     50 meters position - begin timing at the "start" command and stop as the
                      vehicle crosses the 50 meter position. 
     75 meters position - begin timing at the "start" command and stop as the
                      vehicle crosses the 75 meters position.
    100 meters position - begin timing at the "start" command and stop as the
                      vehicle crosses the finish line (100 position).

Performance Assessment:

 1. Student will calculate the average speed and the average velocity for each
    group using the following formuli:        
                   
      speed = distance/time             velocity = distance & direction/time
  
 2. Student will plot on a graph velocity vs time and speed vs time.

 3. Students will measure the time of a vehicle at 5 five distances from "0" 
    to 100 meters and plot the acceleration of the vehicle on a graph. 

Conclusions:

 1. Students learned the difference between speed and velocity by measuring 
    distances and times and using formuli to calculate speed and velocity.
 2. Students learned how to use data from a table to plot a graph showing the 
    information.
 3. Students learned that motion is defined in relative terms.
 4. Students learned that acceleration is a rate of change in speed or 
    velocity (increase or decrease). 

References:
 
   Hewitt, Paul, Conceptual Physics, Scott Foreman Addison Wesley, 1999
   pp 10-15