Angle and Friction Matter for Desk Tennis Spin
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• Physics 16, s78
The angle of incidence and the friction of the floor are the one components that impression the spin of a desk tennis ball after it collides with a inflexible floor.
The gamers competing in Sunday’s finals of the World Desk Tennis Championship earned their locations within the video games partially by having the ability to management the velocity and spin of the ball on every return shot. Now Théophile Rémond of the College of Lyon, France, and his colleagues have uncovered the components that decide a ball’s rotation fee when it rebounds from the desk [1]. Spoiler alert: It’s the angle of incidence at which the ball strikes the laborious floor and the friction of that floor. Rémond cautions that the examine solely considers laborious surfaces—ones that don’t deform—and so solely applies to the ball–desk interactions. Interactions between the ball and the paddle—a mushy floor—might produce other determinant components.
For his or her experiments, the crew used a spring-loaded system to fireplace a desk tennis ball at a glass plate, various the angle and velocity at which the ball hit. They then used movies of the ball’s interplay with the plate to measure the velocity, rotation fee, and angle at which it rebounded.
For incidence angles under 45°, the crew noticed that on impression, the ball rolled alongside the floor for a fraction of a full rotation earlier than bouncing off, a sequence of occasions that set it spinning. For bigger incidence angles, the ball slid as an alternative of rolling, lowering its rebound spin. Trying then at friction, for giant angles of incidence, the crew discovered that the magnitude of the spin and velocity of the ball have been each set through the sliding section and have been depending on the friction of the glass plate. The parameters each elevated with rising friction saturating at values that have been decided by the ball’s rolling movement at small angles of incidence. The crew additionally noticed that deformation of the ball upon impression had no important position on the ball’s rotation fee, which Rémond says is an attention-grabbing remark however one he thinks is unlikely to impression the actions of desk tennis gamers.
–Rachel Berkowitz
Rachel Berkowitz is a Corresponding Editor for Physics Journal based mostly in Vancouver, Canada.
References
- T. Rémond et al., “Indirect impression of a buckling table-tennis ball on a inflexible floor,” Phys. Rev. E 107, 055007 (2023).
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