Velocity and speed are often confused, but they are very different.
We define the average speed as the distance traveled divided by the time it takes to travel it. Distance is step size times the number of steps, irregardless of direction. Speed is a scalar value and is always positive or zero.
Average Speed = distance / time
Average velocity is defined as the displacement divided by time. Displacement measures where you end up relative to where you started. Velocity is a vector value. It has magnitude and direction.
Average Velocity = displacement / time
Even if you travel a great distance but return to your starting point, then your displacement is zero and your average velocity is zero.
Slide the green/red controls in the interactive diagram above to compare speed and velocity for different time spans over the time/position curve.
Subject Index for all interactive diagrams
interactagram.com - Physics - Kinamatics - Position, Velocity, and Acceleration - Speed vs Velocity
Source Flash: speedVsVelocity.zip
Visits since 5-29-09: 1336
Interactagram.com uses third-party advertising companies to serve ads when you visit our website. These companies may use information (not including your name, address, email address, or telephone number) about your visits to this and other websites in order to provide advertisements about goods and services of interest to you. If you would like more information about this practice and to know your choices about not having this information used by these companies, click here.