Galileo tried to prove that all falling objects accelerate downward at the same rate. Falling objects do accelerate downward at the same rate in a vacuum. Air resistance, however, can cause objects to fall at different rates in air. Air resistance enables a skydiver’s parachute to slow his or her fall. Because of air resistance, falling objects can reach a maximum velocity or terminal velocity. In this experiment, you will study the velocities of two different falling objects.


  • Use a Motion Detector to measure distance and velocity.
  • Produce position vs. time and velocity vs. time graphs.
  • Analyze and explain the results.