Speed+and+Velocity

http://www.physicsclassroom.com/Class/circles/u6l1a.cfm.

http://www.newton.dep.anl.gov/askasci/phy99/phy99x92.htm

http://www.glenbrook.k12.il.us/GBSSCI/PHYS/CLASS/1DKin/U1L1d.htm

http://www.regentsprep.org/Regents/physics/phys01/velocity/default.htm

http://hypertextbook.com/physics/mechanics/velocity/