Average vs.
Instantaneous Speed
A GIF Animation
During a typical trip to school, your car will undergo a
series of changes in its speed. If you were to inspect the
speedometer readings at regular intervals, you would notice that it
changes often. The speedometer of a car reveals information about the
instantaneous speed of your car; that is, it shows your speed at a
particular instant in time.
The instantaneous speed of an object is not to be confused
with the average speed. Average speed is a
measure of the distance traveled in a given period of time; it is
sometimes refered to as the distance
per
time ratio. Suppose that during your trip to school, you traveled a
distance of 5 miles and the trip lasted 0.2 hours (12 minutes). The
average speed of your car could be determined as
On the average, your car was moving with
a speed of 25 miles per hour. During your trip, there may have been
times that you were stopped and other times that your speedometer was
reading 50 miles per hour; yet on the average you were moving with a
speed of 25 miles per hour.
For more information on physical descriptions of motion,
visit
The
Physics Classroom. Specific information is available there on the
following topic:
This page was created by
Tom
Henderson of
Glenbrook South
High School.
Comments and suggestions can be sent by e-mail to
Tom
Henderson.
This page last updated on 2/21/97.