produce a net lift. This mechanically induced 
circulation-called Magnus effect-illustrates 
the relationship between circulation and lift 
and is important to golfers, baseball and tennis 
players as well as pilots and aerodynamicists. 
The curvature of the flight path of a golf ball 
or baseball rcluites an unbalance df force 
which is created by rotation of the ball. The 
pitcher that can accurately control a .powerful 
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