Purpose: To demonstrate the relation y=(1/2)gt²

The apparatus consists of a cord approximately 3.5 m long with weights tied to it at such spacings to produce constant time intervals between the sounds of the weights hitting the floor. The length of the cord is about 3.5 m and the spacings of the weights are calculated to produce a time interval of 0.15 sec.

The class should first be shown that the weights are distant from the bottom y according to the relation y = (1/2)gt² for Dt = 0.15 sec. Thus, since t = Sum[ (Dt)_i ], the following table shows the predicted y values for constant Dt:

    t (sec)   y (cm)

     0.00        0
     0.15       11
     0.30       44
     0.45       99
     0.60      176
     0.75      276
      

Stand on the desk and hang the cord over a pie tin. When released, the sound of the weights hitting the tin will occur at constant intervals.

Please wrap the cord back around the cardboard when done.

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