We have developed a system to measure the motion of a car with very good precision. It requires a laptop computer and a standard sensor interface. The added parts are relatively simple and inexpensive, and can be connected to a variety of cars easily and quickly. Using this system, we are able to derive the horsepower and torque versus engine speed for any manual transmission car. Students enjoy the lab because it gives them an excuse to floor their car but it also produces remarkably good data.

1.
Inclusion of this effect was done at the suggestion of our referee.
2.
K. Newton et al., The Motor Vehicle, 10th ed. (Butterworth, 1983), p. 48.
3.
J. Fenton, Handbook of Vehicle Design Analysis (Mechanical Engineering Publications, London, 1996), p. 580.
4.
http://www.goshen.edu/physics/horsepower/index.html.
5.
R.H. Barnard, Road Vehicle Aerodynamic Design, (Longman, Essex, 1996), p. 21.
6.
http://www.pumaracing.co.uk/power3.htm.
This content is only available via PDF.
AAPT members receive access to The Physics Teacher and the American Journal of Physics as a member benefit. To learn more about this member benefit and becoming an AAPT member, visit the Joining AAPT page.