| 摘要 |
A speed-sensing projectile (10) such as for example a baseball includes a generally spherical body (16). An inertial switch (42) is positioned within the body (16) and is actuable between open and closed conditions in response to accelerations of the body (16) greater than a threshold value. A processor (160) also within the body (16) is responsive to the inertial switch (42) and calculates the average speed at which the baseball is thrown over a fixed distance. A visible display (64) on the body (16) is in communication with the processor (160) and displays the calculated speed.
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