If an adult can buildup a pressure of 9kPa when blowing air through a straw then the pressure drop will be 0.5*1.25*v^2. But if I want to compute the air volocity in the straw how can I know the pressure in the other end of the straw as a function of its dimensions?

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    $\begingroup$ If you are on the surface of the Earth, then the pressure at the other end should be just 1 ATM. $\endgroup$ – BioPhysicist Jun 4 '18 at 1:33
  • $\begingroup$ @AaronStevens So if the pressure drop is 9kPa I get a velocity of 120 m/s. This can't be true. $\endgroup$ – OMGsh Jun 4 '18 at 13:10
  • $\begingroup$ Also if the pressure would be 1 ATM I guess the air speed at the end of the straw would be 0. $\endgroup$ – OMGsh Jun 4 '18 at 13:17
  • $\begingroup$ How are you getting 120 m/s? I am getting about 1/10 of that with my calculations. $\endgroup$ – BioPhysicist Jun 4 '18 at 14:09
  • $\begingroup$ @AaronStevens 0.5*1.25*v^2=9000 --> v=120 m/s. $\endgroup$ – OMGsh Jun 4 '18 at 19:29

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