Things to Understand about Average Velocity.

1. Average velocity is not the same as average speed.

• Average velocity has direction, average speed does not.
• The magnitude of the average velocity, which is a scalar, is not equal to the average speed in general.

Now do the following. Taking a value for the average velocity from the simulation, calculate its magnitude from the components v_x,av and v_y,av using the Pythagorean formula,

|v_av| = square root of "(v_x,av)² + (v_x,av)²".

Compare this magnitude to the average speed, v_av. Is it equal to, less than or greater than the average speed? Can you explain the numbers you observe?

Since the magnitude of the average velocity is in general different from the average speed, we use different symbols for the two quantities. The notation v_av is used only for average speed while a more elaborate notation is used for the magnitude of the average velocity, as in the equation above.