Can model car performance be measured and compared by the Race Timer?
If car performance needs to be measured, then the Speedometer mode can do this. The measured speed of the car at the Race Timer gate over a specific track will indicate the energy of the car and so it’s efficiency over the track. The car’s energy is calculated by the equation of ½ *M*V^2 (Kinetic Energy (KE) measured in Joules) where M is the mass of the car in Kg and V is the speed in metres per second (m/s). The speed of the car can be calculated in m/s by multiplying the Race Timer Speedometer display in Km/h by 0.277778. Or you can get the speed in m/s, and other units, from the data output via the datalink connection. If you measure the height of the release point above the Race Timer height, you can find the starting energy (the potential energy or PE) of the car. PE = mgh where m = mass in Kg, G is gravitational acceleration (9.8m/s^2) and h is the height above the Race Timer in metres. The difference in energy between the PE and KE indicates the efficiency of the car; or the change of PE into heat and sound. 0 difference would indicate a perfect, frictionless car and track. If you want a ratio, divide the difference by the starting energy (PE-KE)/PE. Multiply by 100 to get a result as a percentage (%).
Using the datalink version of the Cook’s Projects Race Timer and Speedometer is ideal for this type of data analysis and provides the most accurate information. Not only will the output be stored with a much higher precision than available on the LCD display, but the data can then be cut and pasted into a spreadsheet where the calculations, described above, have been programmed. The datalink capture of every car passing the sensors also allows lots of cars to be tested in a batch before analysing the results.
We have now developed the software to complete the calculation for you. Check out the project by clicking the button below or watch the video at
