| 摘要 |
<p>A body moved through the air has to overcome a pressure resistance as well as a friction resistance. A ball-shaped object is particularly affected by the pressure resistance. The braking effect is dependent on the difference of pressure acting on the front and on the rear of the ball resulting in the creation of eddies behind the object. The new design of a ball used as a projectile in a paint-ball game is provided with a multitude of depressions distributed across its surface in order to reduce the pressure resistance.</p> |
