The Physics
Factbook
An encyclopedia of scientific essays

Speed of a Baseball: Bird Baseball

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Go to www.killsometime.com and watch the "Bird Baseball" clip.

The video clip is from an Arizona Diamondbacks spring training baseball game. Randy Johnson, the pitcher on the mound, throws a pitch which fatally hits a dove that flies by from the right of the screen. Assume the ball hits the dove three-fourths of the way from the pitcher's mound to home plate.

The following information can be determined from the video clip:

  1. Time from the release of the pitch to the collision
  2. Velocity of the baseball in miles per hour

Assume that the path of the baseball is a straight path from the pitcher's mound towards home plate.

1. Time from the release of the pitch to the collision

Count the number of frames from the point of release to the collision, watching the video clip in Windows Media Player Classic.

Frames - 9 Frames

To find the frame rate, look at the bottom of windows media player classic

Frame Rate - 30 frames/second

To find the time, divide the number of frames by the frame rate.

9 frames/(30 frames/sec) = 0.3 seconds

2. Velocity

Determine the distance from the pitcher's mound to home plate by converting feet to meters.

60.5 feet = 18.4 meters

Determine the distance the ball travels. Assume that the collision occurs three-fourths of the way from the pitcher's mound to home plate.

¾ x 18.4 meters = 13.8 meters

Find the average velocity of the baseball using the formula v = ∆x/∆t.

v = ∆x/∆t
v = 13.8 meters/0.3 seconds
v = 46.0 m/s

Convert the velocity from m/s to mph.

46.0 m/s = 102.9 mph

Willie Feng -- 2005

Physics on Film
  1. Feature Films
    1. Tension in Spider-Man's webs
    2. Speed of a car: Bad Boys II
    3. Speed of a car: The Blues Brothers
    4. Speed of a car: The French Connection
    5. Speed of a car: Le Mans (Steve McQueen 1971)
  2. One Reelers
    1. Speed of a car: C'était un Rendezvous
    2. Speed of a car: The Run
  3. Short Video Clips
    1. Speed of a baseball: Bird Baseball
    2. Speed of a cliff diver: Iraqi Olympic Diving
    3. Speed of a motorcycle: Loading a Bike
    4. Speed of a snowmobile: Snow Jump