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PracticeFinalAns

# PracticeFinalAns - A_nswer name keY-DL-s-ecLast name first...

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_______ A_nswer keY-DL-s-ec- IFirstthreelinitialsoflastnamel 1 1 p2 Last name first name grade (for office use only) 1. A fluid circuit has a pipe containing water which rises a height h, and the cross sectional area decreases to half its initial value as shown. The speed of the flow in the lower section is v: = 10.0 m/s and the pressure is PI = 200 kPa. Any dissipation can be ignored. .' (Jw= 1000kg/m 3 . Useg= 10m/s 2 . "- -+ ,/ :' a) At which point (point 1 or point 2) is the speed of the flow I , greatest and what is its value? The speed,s '.:1reateJ a+ poinl 2. ... r The flow (c urrent) I> COil sla n f rr, :Tz.) , bu~ +he cross ~ec+lonal area is >llloUer a! poi n} 2, A-z., = lA., thus A. 1. V 1 = A, v, ~ VI, = (A, / A'1.)~ = (A, / ( iA 1 )) v; Vz= 2~ - Z.( lD''''/~) v Z. : 2 0 111( S ) V I -= 1 0 ml-" b) What is the greatest value h can have? Hint, the lowest value pressure can have it zero. In ~he abse."ce ol either diii paft" n or' " punlp I we hove ~ P+ IP4l v%.) + eg 4n: o. Choostng hJ ~ 0 and 1 ethn9 ~ = ~ we ~et t t'v z 1. ... /9 h 2:: PI ... -!. e VI" ) one! solvi "9 fOr h, ~ \ V e s h1. : i9 (~1. - Y1.1.) -\- P. / f' 9 2. 1.-) 1. 00' LO J Po ,., (1) ( ro llVS1. l Q 0 "Y';) - ("20 tn/sl -lo (I 000 ~/n1; ) (10t1~) hz. : -~ rn ... IOn' r h 1.: 5" n'\ .J

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Answer key I I I p3 11 1 Last name First name DL Sec First three initials of last name grade (for office use only) 2. Firefighters use a hose to apply water to a fire. Such a hose is shown to the right. a) Why does the hose have a nozzle at the end (in other words, why does the cross-sectional area need to be smaller at the end)? (Hint: does a firefighter want to stand close to a fire or far from a fire?) Because II. -=T. '* A1.V1,.. =A.~ the I sillallt'r end will cause the water tD leave the nOllle wd·h a higher speed. The +ir~fi9h+-er can +hen spr{iy the wa+e~- on +-he .fire t rom fa~+her away. b) A small amount of water (approximately 1 liter) is shown at three different locations as it moves through the hose. On the picture, draw a vector at each location showing the direction of the net force on this 1 liter of water when it is at that location. If the net force is zero then just write a 0 next to that location. E"'plancJ.-o,,: A -') con5+allt "elo(..j~y => F"e~ =0. B ., constant speed, buf l1loflon in a CirL(e =) r=oef is racl i olly inwarcl C JJ cOI1S+a~t ,tirectiol1> but increasin9 ~peeJ ~ Fnei ~S" I t\ +he cli(€Ji 0.' of m;+'on.
An,wer Key IFirst three1initialS of last name [ [ p 4 1 Last name First name DL Sec grade (for office use only) 3.

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