NEW! Compare uniform and changing velocity with one device.  This pull-back double-decker bus starts from rest then smoothly accelerates to a uniform velocity before a quick stop.  Can exceed 5 meters depending on length of pull-back.   Attach a card to its bumper for motion detector data or ticker-timer tape for distance vs. time interval data.  Made of sturdy die-cast metal.  Length: 5" . Click on 'View Larger Image' for .jpg of position vs. time graph created with motion detector.