Flight of a shuttlecock?

During a game of badminton i was watching how the base always faces the racket. Also the plastic ones dont spin but the feathers do. Would anyone like to comment on The physics of this.|||Key to both is drag, air friction, which is D = 1/2 rho Cd A v^2 = kA v^2; where rho is air density, Cd is coefficient of drag, A is cross sectional area, and v is the air speed over the moving body (or the speed of the body through still air). The drag on a shuttlecock is relatively high because A is a relatively large cross sectional area established by the plastic cup or feathers of the trailing end.





And because the weight of a shuttlecock is light, it quickly reaches terminal speed v = sqrt(w/kA) where w = mg is the weight of the shuttlecock's mass m. g is g. This is why, in badminton, we don't see really fast speeds, like 120 mph in tennis serves. In fact, the drag acts as a braking force to actually bring the shuttlecock to a near (but not quite) halt in horizontal speed. At which time it falls nearly vertically to the gym floor.





As to the spinning of the feathered kind, that's because the feathers are not flat with the flow of air over them. They are twisted slightly like fan blades. So the change in momentum of the air flowing over the feather blades causes a twisting force on the shuttlecock.





The plastic cup, on the other hand, has no such blade shape or other form to cause the air flow to change momentum and cause a twisting force. The cup has holes, to modify the A value so it matches the regulation drag value of the feathered variety, but that's it.|||Physics is everywhere because mass and energy are everywhere... physics is the study and understanding of mass and energy.

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