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.

As an added benefit, students see real-time graphs of position and velocity versus time while they are riding in the car experiencing the very motion being plotted. This becomes a wonderful reinforcement of the popular labs in which students move an object in front of a range finder. In this case they are riding in the moving object and experience all the pseudo-forces that arise in the accelerated reference frame. Back in the lab, they analyze the graphs in a spreadsheet program. Imagine the sheepish looks on students' faces when the professor points out the clear graphical evidence that they broke the speed limit.