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View Full Version : Elevation and tennis


MTXR
07-10-2009, 01:10 PM
i recently played in California coming from the Mid West. The elevation is quite a bit lower in California where i was playing. I noticed the tennis balls were bouncing a lot higher compared to the Mid West. Does elevation effect ball bounce? There could be many factors like tennis court, player, etc... but I have never seen the ball bounce so consistently high.... and my shots seemed to cut through the air and fly on me a bit more...

WildVolley
07-10-2009, 01:18 PM
My experience has been that balls bounce higher at high elevations than at lower elevations. I recall the balls bouncing a lot when I played in Santa Fe. I assumed the greater pressure difference between the ball and the outside air made them bouncier.

I mostly play on courts ten to 100 feet above sea level and I don't notice the ball bouncing particularly high.

dmtree
07-10-2009, 01:51 PM
ball fly further and bounce higher at elevation. hence high-altitude balls, which don't bounce as much. i live in Colorado, the game is faster here than at sea level.

Gh0st
07-10-2009, 02:56 PM
I play at 5000+ feet. I haven't played at sea level in a long time. Might have to try it again soon just to see how different it plays.

MTXR
07-10-2009, 07:54 PM
oh wow.... then i guess there was just more top spin.....


I don't have problems in the mid west like i did when i was in San Francisco

SystemicAnomaly
07-13-2009, 07:53 AM
I believe that there are 3 (related) factors for balls acting differently at hihger altitudes than at lower altitudes. As mentioned previously, the bounce at higher elevations will be greater because the pressure inside the ball is so much greater than the outside air pressure (probably less than 2x at sea level but greater than 2x at high altitudes for standard balls).

Because of of the thinner air (lower air pressure) at high elevations, the ball will experience less air drag (friction) so should also fly thru the air faster (since it won't slow down as much as it would thru thicker air). Lastly, spin will probably have less effect at higher elevations than at sea level. This is due to the lesser Magnus Force (http://en.wikipedia.org/wiki/Magnus_force) (F) at higher altitudes. With smaller Magnus Forces acting on the ball, less flight deviation due to spin will occur.

http://upload.wikimedia.org/math/1/b/d/1bd91ba73bba3d3db412d544d4ca9fd3.png

where ρ = density of the fluid and l = lift coefficient

I believe that High Altitude balls will have more felt (or will be fuzzier) to increase the value of (l) the lift coefficient to compensate for the reduction in (ρ) the density of the fluid (air). The greater fuzziness should also help to increase the air drag on the ball to slow it down more as it flies thru the air. The HA balls also probably have a reduced internal pressure compared to regular pressurized balls.