subaru image from              http://cars.88000.org/90__Subaru_Impreza_WRX_STi,_2005.htm

tire traction a friction           http://www.worsleyschool.net/science/files/tires/andfriction.html

tire images from                  http://www.tirerack.com/indexA.jsp

forms of energy                  http://www.eia.doe.gov/kids/energyfacts/science/formsofenergy.html

how an engine works          http://www.autoeducation.com/autoshop101/engine.html

automobile engines             http://www.familycar.com/Engine.html

How horsepower works      http://www.howstuffworks.com/horsepower.htm

Horsepower                       http://en.wikipedia.org/wiki/Horsepower

Fundamentals of Physics 8th Edition  2008, Walker, Jearl