• Measure the drop time of a small plastic ball (or any object
  that isn’t so heavy that it damages the force plate upon impact).
• The Pasco force probe is located 1 or 2 meters above the
  floor, suspended by a ring stand, oriented with the force sensor pointing
  down. A small plastic ball is pressed lightly up against the sensor and then
  released. The ball lands on the force plate, resting
  on the floor, directly beneath the force probe. The event is graphed using
  logger pro, (in the picture above, the top graph is that of the force probe,
  and the bottom the force plate). The moment of release and moment of impact are indicated on the two logger pro graphs. Time measurements are only accurate to
  .02 seconds.
• Force probe and labpro device is located in L35, section
  B2. Force plate is located in L02 section B3.
• Note: You might think that a photogate would
  be the more effective and convenient way to measure the release time. But
  for some reason, when the photogate is used drop times are consistently measured
  to be .04 seconds too short. Which amounts to about 10% error.