This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: Exam 1. Wednesday, February 13‘“, 2008 PHY 252 Name; Sowmom Each question is worth 25 points. Answer all three questions. Be careful to justify your answers —
most of the credit will be for clear explanations of the physics. Do not leave questions
unanswered. Even if you cannot get the ﬁnal answer, show me clearly what you know. 1. A string of length L that has a mass per unit length of p, is under tension F and is clamped at
both ends so that the ends cannot move. A transverse standing wave of type y(x,t) = Asin(kx — wt)+ Bsin(kx + cut)
is set up on the string.
(a) Which wave is traveling in the x direction? Asin (kx — wt) or (Circle one.) (b) Give an expression for B in terms of A. At ec=o Collagen.) we reclaim 3(a,:t)=o
.‘. AvatC—wx) + es'utawe) :— o
nﬁs‘méwi) +Bs'm (nut) 20 => 8 =9 —'—_ X. (c) What possible values can k have? Ail: oerL, we “2M {'juJ‘e) =‘9 “ (Salim“mg +5L4£”L*w13) ': o
or lﬂs'mk’Lcoeui =0 = [r = _ = it?
c ShayH3) Efmﬁagssibmmaclm whav: L m .5 K L ‘4: '17:3  ‘1‘
vmﬂv=dfz=%e> w=J§ng a4
(e) What is the velocity of the string along the y direction at point x at time t?
Velociéj ‘»=. 35 : AwicoeCKxrwt) ~m¢Kx~wﬂj VY‘ (i) What is the acceleration of the string along the y direction at point x at time t?
 2 n s
Accelerai'wualau a = 3 a = __ ,4 “)1. [sm( Kan th) + SmﬁKx~wi~ﬂ
81‘
2 . _  . .
= _wﬂ L2 (144. sMWosallaJ‘orl (g) What is the velocity of the wave along the x direction at pointx at time t? Utgw 22F (h) What is the acceleration of the wave along the x direction at point x at time t? “M5” “1°51: 2—3" 2'" «amassed! "’5 % DOM ‘Lo and“ 'TLL mum's Plume MW aid. Idea4% Exam 1. Wednesday, February 13'“, 2008 PHY 252 2. A deepsea diver is suspended beneath the surface of Loch Ness
by a 100—mlong cable that is attached to a boat on the surface.
The diver and his suit have a total mass of 120 kg and a volume
of 0.0800 m3. The cable has a diameter of 2.00 cm and a linear
mass density of p:1.10 kg/m. The diver thinks he sees
something moving in the murky depths and jerks the end of the
cable back and forth horizoutally to send transverse waves up
the cable as a signal to his companions on the boat. How lon does it take for the si nal to reach the boat at the
surface? (Hint: This is similar to the danglingrope homework problem,
except here you need to include the buoyant forces on the diver
and on the cable when calculating the tension as a function of
height along the rope. Density of water = 1000 kg/m3.) Fl'rst’ m M to .ua RELc 41PM QC.
"reunion ad” or. = Me‘ﬁLtoﬁM + mead” salesJalabe
_ magma claim—  10W spatula Wm.
F62) 2: mg + ptch  pwvnj  Pw(TFD’I./a)o¢j Fox) = (m ~Pon)j +3(/4c‘7TPaP:/‘r) 0“ 5 (Liho;
Mamet»dede ‘2 U'Cx) = = )3;th Tim to mutt 7&0? 01+ ac: n (=l00m) LA k h LL
1: 1: $5533 ‘“ II—af‘ox do: 2 JEEJ(Q+bag_)]o O O 7t— : {LEE/(Mm — J3]
=7 (M — PanLq' = (not:1 — woo kﬂlﬁxaoaooHK) xﬁeowls‘) = 3(uC—‘IT'QJDE/4) = clSDx<lJo nrwoaoxézmﬁlzr) CL
CL = 391.000”
lo
5 = enrol; HIM (Keep 524.5135.) 'I
.‘ 7!: = 1 Llo ‘ . , _ .l 7
 lawnC i “[V(392000 +9 Rialzxzao) Sqaj t: 3.851 sec 35tj.jt§5 h)“.
C Cream: is given for ﬂood 911113153. 1 calculi care, too Much about {she answer. Exam 1. Wednesday, February 13'1', 2008 PHY 252 3. Two very large open tanks A and F contain
the same liquid. A horizontal pipe BCD,
having a constriction at C and open to the air
at D, leads out of the bottom of tank A, and a
vertical pipe E opens into the constriction at
C and dips into the liquid in tank F. Assume
streamline ﬂow and no viscosity. If the
crosssectional area at C is onehalf the area
at D, and if D is a distance in below the level
of the liquid in A, to what height h; will
liquid rise in pipe E? Express your answer in
terms of h. Appid BQFHOUL'ILLI'IS eiurtiau. to the top tank_ 53% dﬂzﬂczan :0 A ‘2.
Po +33%; + o : F’3 +0 +301): L: Pc +0 +4391): .2 P°+o+1i~pvo ._ P°+o+lipya
L_____.__.___.__1 \___________J 1
To? O£ A At 3 Ai‘ C. Ai n oPe"———Jntoq..rdo Since EMA. D Luau; 2914.1 5M JIMfer, we:vn).'_!p3=Pn=Pei ® 50, Shame PD+P3L1I = Pls+§Pv$ 2 Po +359"; => ———> ® ...
View
Full
Document
This note was uploaded on 05/11/2008 for the course PHY 252 taught by Professor Treacy during the Spring '08 term at ASU.
 Spring '08
 Treacy

Click to edit the document details