Anyway, a 5m track was laid out, with a light sensor at each end, these were connected to a computer and were used for measuring the time taken to traverse the track. A computer program was set up to calculate the minimum time a car should take to run the 5m based on the weight of each car and the engine stored in a control spring...this showed quite a considerable fluctuation in the spring constant of the supposedly identical springs!
Anyway, after this, using various bits of data from the test, and other assumptions made, a set of calculations had to be done to calculate velocities, accelerations and times for the movement of the car. I did these calculations using Excel, with which you are able to produce a rather snazzy spreadsheet where changing one piece of data such as the weight of the car, alters everything!
By the way, after hating Excel for the last 18 years of my life, I have discovered the joy of these snazzy spreadsheets and have introduced The Carpenter to them, who now uses them for calculating information for organ building.