Passage VII

Some students performed 3 studies to measure the average horizontal speed of a baseball along its flight path under different wind conditions.

In each study, a pitching machine, a catcher, and a camera were positioned as shown in Figure 1. A measuring tape was extended just above the imaginary line from the pitching machine to the catcher.

When no wind was blowing, the students caused the pitching machine to pitch the baseball at a speed of 36 meters per second (m/sec). While the baseball was in flight, its image was recorded on the film in the camera every 0.1 sec. The resulting photograph showed 5 images of the baseball below an image of the measuring tape (see Figure 2).

For each interval defined by adjacent images of the baseball, the students measured the horizontal distance between the images (using the image of the measuring tape) and then divided the distance by 0.1 sec to determine the average horizontal speed of the baseball (see Table 1).

Study 2

When the wind was blowing from east to west with a speed of 15 m/sec, the students repeated the procedure used in Study 1 (see Table 2).

Study 3

When the wind was blowing from west to east with a speed of 15 m/sec, the students repeated the procedure used in Study 1 (see Table 3).