Re: I don't understand the difference between speed and velocity.

Velocity is speed with a direction!  If you talk about the speed
of something you aren't telling what direction it is going in, but
if you also give the direction you are now talking about velocity.
This seems a bit picky, but it is important to keep descriptions
precise so that people know what you are talking about, especially
physicists!

- - John Link, Physicist
    MadSci Admin