A lift force that acts on a spinning projectile. The spin creates a region of relative low velocity and high pressure on one side of the projectile, and a region of relatively high velocity and low pressure on the opposite side. The pressure differential creates the Magnus force, a lift force directed from the high pressure region to the low pressure region. The Magnus force causes the trajectory of the projectile to deviate in the direction of the spin. Therefore, the Magnus force of a top spin is directed downwards, causing a tennis ball, for example, to rebound low and fast. The Magnus force of a backspin is directed upwards, causing the tennis ball to rebound high and slow. See also Magnus effect.
Subjects: Sports and Exercise Medicine.