The curve





                                   v_t                  Magnus force
 Pitch type     spin direction    (mph)      S      size (N)     direction
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  fastball        backspin        90.0     0.21       0.93       mostly up

  changeup        backspin        80.0     0.14       0.74       mostly up

  curveball       topspin         80.0     0.14       0.74       mostly down
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