Designed for use with a Makey Makey, this Scratch game will calculate rate after you measure the distance on a track and time of travel for your toy car. You can measure the speed of the car at the beginning of the track and the end of the track to see the difference in the acceleration from the deceleration. Hook your Makey Makey up as follows: Acceleration Start- Space Bar (and earth) Acceleration End- Up Arrow (and earth) Deceleration Start- Down Arrow (and earth) Deceleration End- Right Arrow (and earth) You'll have to build switches at each point you want to start and end the timer. Some Hot-wheels tracks have great contact switches and you can just add copper tape to these for your switch. A full tutorial is available at MakeyMakey.com.
Hat tip to these Scratch stopwatches and timers for inspiration on my scripts: https://scratch.mit.edu/projects/10270586/#player https://scratch.mit.edu/projects/484897/#player