Physical Science Lab #2

Acceleration Due to Gravity

Theory

x = vot + 1/2 gt2, where x is the position relative to the starting position, vo is the starting velocity, t is the time and g is the acceleration due to gravity (g = 9.8 m/s2). Down is considered the positive direction for this equation. In this lab there is zero starting velocity.


Procedure

The sparker timer gives off sparks that mark the ticker tape with black dots. These dots are given off at a constant rate of 50 dots per second (or in other words, there is a 0.02 second time interval between dots).
  1. Cut off a piece of ticker tape about 1.2 m long. Tape a mass to the bottom of it and run it through the sparker timer. (I'll show you how.)
  2. By counting dots from the starting point you can figure out the time since the mass was dropped. (The time elapsed = 0.02 s/dot x number of dots since the start.) You get the distance with a meter stick. Use this to make a table of position vs. time.
  3. Graph the equation form the theory to compare theory and experiment. You can do this by extending your table to include theoretical position values. The table of data and calculations should look like:


    4. Measured       Number of dots      Measured      Calculated
    Position                                        Time                Position
    (in meters)                                     (in seconds)      (in meters)
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