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# Speed of a Baseball: Bird Baseball

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
2. One Reelers
3. Short Video Clips