Physics 211

VideoPoint

Hints forVideoPoint[TM], for use in Horizontal and Vertical Motion

• Whenyou open the "Clip 3" movie found in the "Horizontal and Vertical
  Motion" folder, choose twofeature or object to be located (that will be the balls)
  and then "OK."

• Position Calibration: Under the "Movie" menu choose "Scale Movie..." Enter
  the scaling factor (from the other clips). Follow the directions and click on two
  points defining the scale.

• Frame Rate Calibration: Scan through the movie and determine the frame rate,
  by comparing the number of frames to the time it should take for the ball to hit
  the ground. Under the "Movie" menu choose "Select Frame Rate..." Select
  "Other" in the pop-up menu and then enter the frame rate of this film.

• Step Size:Choose "Set Step Size" under the "Movie" menu so that you will
  obtain a reasonable number of data points.

• OriginThe origin is in the lower left hand corner of the frame by default. Move
  it to a more useful place by clicking on the orange-yellow origin point and
  dragging.

• Make the Coordinate Systemswindow active by clicking on it once. Change the
  name of the data point "Point S1" to "Left Ball" by clicking on the name. Double
  click beside the name, and when you get a chance, select the "Leave Trails"
  checkbox. Repeat for the "Right Ball."

• Make the window showing the movie active.
  icon on the side bar.

Click on the Collect Data

• If necessary, adjust the data point position for each frame by clicking on
  the arrows of the point - adjust icon on the side bar.

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