Great device to help students connect physical motion with the concepts of constant and changing velocity. Assembled, finished, and drilled for use as a bifilar pendulum and for demonstrating acceleration in linear, circular, and rotational motion. Instructions for filling included. May be mounted to a M-22 Wooden Crash Car or to a Pasco Dynamics Car, Pascar, or Gocar using M-03-H holder (cars and holder not included.) A carpenter bubble level accelerometer is included.   Student laboratory activity booklet available - see Tips and Activities.