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Unformatted text preview: Quiz 3. Monday, February 11m, 2008 PHY 252 So 1. U'TIOIU Name: 1. Identicalsize lead and aluminum cubes are suspended at
different depths by two thin wires in a large container of water.
a. Which cube experiences a greater buoyant force? (1 point)
The. buodan‘t force depevals. on like
Volume oS displaced waiter, Lolath is the
same for both. Cubes, The. buogaut jar:95. are l‘deu‘bl'c.¢(, . 7“ =
b. For which cube is the tension in the wire greater? “Tension == wequa't of; Mass — lanai14nd: force "The heavier Mass] lead.) glues the greater tens/om it"
since the ioWan't'fOr‘Ceé are £119 same
0. Which cube experiences a greater force on its lower face? (1 point) *4 The. lower cube has the greafefforce.
Fate " PXA = (P.+ng)ﬁ. The. M Chaise L04 iLe .LoﬁeiL. h— 63515th d. For which cube is the ifference in pressure between the upper and lower faces greater? PW : pﬂ ALL wt.“ Ar = %@4ﬁlaaq(lpoint)
beaniem, war MJ. ,(ecoer Surf:1 ofwcdg Sum(.2 :Hq,
auLeAMtLaSWJ LotLasm, F0 2. A cable, of density pc and crosssectional area A, is suspended vertically
in the ocean (density p0) to a depth 11. Derive an expression for the tension
in the cable as a function of depth z, where O S z 5 h. Tension = wéGLt gig cable Below 2
 bubdau'tjforce an allele lacglow 2 2:}: :: mass of Cable belowz x5 — displace»! Mass ofwd‘erloelowz. 23 :: ﬂaw2h “PORCH1):? T62) = AﬂCk2)(Pcpa) ﬁr. ‘ Ulla»; 11.21) tCMLLM ::=O/ $14,144
Um P¢=Pa / FEWJ»: :0 Si—Ma :éLe (.4194: amijloa‘éi'uj Quiz 3. Monday, February 11‘“, 2008 PHY 252 3. The diagram is of a horizontal tube with a circular cross section everywhere and a radius of
10.0 mm at the left and right ends, A and C. The tube narrows in the middle, at B, where the
cross sectional area is reduced to onequarter of that at the ends. Water (incompressible)
flows out at C at a steady horizontal velocity of 5.00 m/sec. You can assume that there is
steady, nonviscous, laminar (streamline) flow everywhere. The diagram shows the tube and the streamlines. 5‘00 W560 1
Continuity: d—V = Av Bernouilli: P + pgy + E pv2 = constant dt
a. What is the velocity of water at the input end A? (1 point) no t amidKi _: aﬁuz :: AC1”; : AAA}:z Az=HA)
cit AL \ “ u}:u;_= Sioomise¢ b. What is the velocity of water at B? (1 point) At 3/ :Hm. Wto i6“ ﬂ—am=eae=r4m =2 Ua=Aevz = aria—9+ Ji  +715
c. If the pressure at A is 3,800 torn, what is the pressure at C in pascal? (1 point)
(A merciful hint: latm = 760 torr — you should know this!) ram EMM'S SIMu. {36:39 thﬁu)motvhzvc t‘. 9c: pA
' p4 = aaootcer (div4 x insP4 : KXIDSIPa. %
?60faﬂ in. 54:044.
(1. What is the pressure at B? _ (1 point)
Use gamma 5,, = 3,, _ pp, + 35pm? = F‘stip”: 2 pvipczwc)‘
1 pﬁripv: : P3 +8911: (51m. 7),, =14) P5 = PA  $2597): '. pg =5‘lDEPa "‘ 15x Ciaookjlmﬂx (Suds)! = 312:500 Pa. 3 3424b“ _* e. For a bonus point, can you w briefly how the water flow relates to the pressure
difference between A and C? (1 point) From Cc) we. W PHMJL paw”; TM 1A “0 PM“ loa‘irweui 44an C, W twice M—o—jm CMIELL “WW"km are“)? Sim ﬁlmy: m aheadj, 76W 4W— uo fﬂwfmea. “my; La Maureen‘s fme feralAHA. Tim 5M Made.0 at 0L ﬂuid rah 34 13M absent; erg aim (loaﬂ wrwoiddéd)
Heart, diesrm. M ION/mm C’Jloafelmm—lﬁino:t ...
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 Spring '08
 Treacy
 Force, Tim, Lolath

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