Question

Generally, adults are able to exhale 1.5 liters of air in ~ 1.0 s. if a person blows air at this rate through a drinking straw having a diameter of 0.60 cm. (a) What is the speed of air in the straw? The air is directed horizontally across the upper end of a second vertical straw which has a length of 1 = 30 cm above the level of water in the trough- as shown in the figure. (b) To what height h, does the water level rise in the vertical straw? (13 points) 1 h

Answer 1

(a) The flow rate for the air velocity is, AV = AV At AV At VE AV At 1 4 1.5x10-3 1.0 2 (0.6x10-2) = 53.1 m/s (b) The pressure difference is, Pi +5 px} = P + a použ P.-P = APPLY = (0.5)(1.29)(53.1) = 1.818 kPa P = P,+ Phg P2 - ? h= Pwg 1.818x103 (1000)(9.8) = 0.1855 m =18.55