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Unformatted text preview: Circle instructor: Morrow or Demirov 1
Lab period: A” f I N 4
Name: 5 0“ UT 0 5
Student Number: MEMORIAL UNIVERSITY OF NEWFOUNDLAND
DEPARTMENT OF PHYSICS AND PHYSICAL OCEANOGRAPHY Physics 1051 Winter 2012 Term Test 1 February 10, 2012 INSTRUCTIONS: 1. Do all questions. Marks are indicated in the left margin. Budget time accordingly. 2. Write your name and student number on each page. 3. You may use a calculator. All other aids are prohibited. 4. Write answers neatly in space provided. If necessary, continue onto the back of the page. 5. Do not erase or use “whiteout” to correct answers. Draw a line neatly through material to
be replaced and continue with correction. 6. Assume all information given is accurate to 3 signiﬁcant ﬁgures. 7. Don’t panic. If something isn’t clear, ASK! SEE LAST PAGE FOR SOME POTENTIALLY USEFUL
F ORMULAE AND CONSTANTS For ofﬁce use only:
I 1 2 3 4 total Circle instructor: Morrow or Demirov 2 Name:
Lab period: Student Number: [10] l. A 0.85 kg mass attached to a spring with a force constant k=150
N/m is oscillating on a horizontal frictionless surface with a
maximum speed of vmax=0.35 m/s and its position from
equilibrium can be written as x(t)=A cos(wr + (p). .p...«.... (a) What is the total mechanical energy of the system? Eﬁém’l/ 1 Way
2 :1 ’ k. ‘, "4‘9
@\E g (ma/{Ar (a 35 v/)
/ a 0; 6958/ J7 (b) What is the period of oscillation? —" M
And: A} a) ad: ,jf : 8/35 0'" (c) What is the amplitude of the oscillation?
ﬂag it) ﬂy; n) P&: 'Z/maa: 4V A): “may v 012‘
A g g frog/U4 writ/U Z ((1) At t=0, the position of the mass is FA/Z and it is moving in the positive x direction.
Find the phase constant (p and initial velocity v(0). a} {:0 1’7 r g C“? c: a: : ﬂ (:05 ¢! if» (adv/(OK?) 5
7‘6? ﬁ,;«¢ﬂ4/Afllr gz‘qm I‘S [ﬁr/“IT 0% r
, I ' ‘ L 4/{Zl}wv/77m/~§.r ét/ WI“ >
a"; 4 ’/9/«t/ {I‘m g9 : »0,&ng4mx /;Z_§ Sme’
f» MM5/ 49/6 Q7:‘/'9¢7gf‘w/‘ : Mm We 12w; per 3 [>1 4/(6) {‘1 @.05’” ﬂajié way .4 r0 02/4,,»«1235 I §M ﬂ tar/M) ;[email protected] 3595/ Circle instructor: Morrow or Demirov 3 Name:
Lab period: Student Number: [10] 2. (a) In the following, assume that the speed of sound in air is 343.2 m/s?
(i) What is the wavelength of sound having a frequency of 440 Hz? <25 “ g
"r o ' / 7/7 , 342.1% g ; , 0”
tr /\ J 3’1 (ii) A tube of length L = 0.65 m is open at one end and closed at the other. Brieﬂy
explain why this tube cannot contain a standing sound wave at 440 Hz. far A,“ 0P1.“ M cm 3448 1 Area 2242562» M" (/0921: ¢¢¢/,anhnaalie «'7’sz 8m?) ‘, i V , ‘x bx" ’I’ , ~ [v A :04me ,1 0'“ z“ "r aygém / W I 2 JV all?” ‘1
r (1,; 1,;  7‘
ﬁQfe B‘np maa% i%%,4:cm/rﬂv (iii) What is the minimum amount of length, AL , that would need to be cut from the
open end of this tube in order for it to resonate at 440 Hz? Cﬂ/agag/r /€l’lf/{L fiIam/ﬁa AHA? 1‘5 /Agr/&w f; ‘i‘ j ,, ("st/V}
GD A if, , 0M ( / / . A”, /‘7//a;/\ [A6 ’,I¢s‘,€ Cf)“ ér/ﬁ * ‘ jiffy/,7 W (iv) In the outline provided, sketch the r———— mode diagram corresponding to the 440 Q
/ Hz standing wave in the resulting tube. DAL _________,
MM? 5 c A! 3" ’Xr (b) Two sources, labeled 81 and S2, emit sound waves, in phase, with frequency 6000 Hz.
They are separated by a distance d which can be changed by moving 82 along the y
axis. An observer (able to hear high frequencies) is positioned 25.0 m directly in front
of source 81 as shown. Assume the speed of sound in air is 343.2 m/s. Y
52 , rﬁ a,
@ f It. >39? X 81 25.0 m ————> (i) What is the wavelength of the sound emitted by the speakers?
org) G? erxxim91 :[0ﬂ572wf7
.6000 5"" v —————~— (ii) The smallest nonzero value of d for which the waves interfere constructively at the observer is d = 1.69 m. What is the next smallest value of d for which the waves
interfere constructively at the observer? £0 ’ﬂ Co?" 5' ILFI/r‘c/“l‘i fizHK/[é/c/z/Lcé’ 4/ {I’M/[199% 6%)
ﬂ“! H61” /wc€, A f g A far censfwMahLe ,‘n H, ﬁreﬂy, 6,} 4/540" ;,,M//i;/ (1:,
r P; S (25372 + a?» 0,0; 79? m :5 02 g» //¢4/n«7 v "Z
7 7: ',// V4 /)r/%/la€yxu5’ / d f ) 2, 2W] » Circle instructor: Morrow or Demirov 4 Name:
Lab period: Student Number: [10] 3. (a) A sinusoidal wave propagates in negative xdirection on a wire of length L=7.3m and
mass m=85g. It takes 0.94s for a point on the wave to travel from one end of the wire
to the other. The period of the wave is T =0.ls. (i) Find the tension on the string. "f Maps/w” 1/: 77’? i 777% ’0‘ s
5:) v 5 M 0 Ugﬁlff : 2 / AV
‘3) IBM?” Odd—é: :? ﬂew! a {f ﬁr? ( 0/5¢% (ii) Find the wave length. l l/ n
7/]; ﬂ BL; v /V « (>1
w/
y
M
\Q
n
m
\s
\1
A3
H
N
‘9
\t
\l
\l
35:. (iii) If the maximum transverse speed is IOm/s, ﬁnd the amplitude. Y/gfmcy 5 4“), ~/ “1%) 2/7 [T , 1.9” ﬂ)” /4’£ w’: {Q 5 5 a A}: $i5/MV .: ﬂag/I ; 67'/5?m ad (X 5‘” ’
(iv) Write the equation of the sinusoidal wave. ’ /
IT a '
"' /I/ee’/ A": 3 03"” ’ MT 5513/5 A 0.77729; ét/zf‘lﬂe 70695 /( ﬂiI a (W l: ” g"? “2* *F‘fiQw,,,,,,_,,, ﬁ/X'M) : (Jr/5'7”? 5M WWW/9r r éQfK/If ) (b) Wire 1 and wire 2 are made of the same material and are under the same tension. The
diameter of wire 1 is twice the diameter of wire 2 so that their cross—sectional areas A .
are related by —A—‘ z 4 where A1 and A2 are the crosssectional areas of wrre 1 and
2 Wire 2 respectively. If waves of the same frequency and amplitude propagate on both . . . P . .
Wires, what 18 the ratio —‘ where P1 and P2 are the powers transmitted by Wire 1 and P2
wire 2 respectively? My
._ Z 2 / ‘v/e [4/ 9&7 ( [0‘7]; plj a 4/ ¢ mrzy€ 14,
{m a 8:» /9/ $6 7/]
:' v“ X —/
P «(/11 4/;
(1/ I It r [1/ fé”?
I.“ a 9/9“ 5’ X
4" Saferwxéxgg’ 1;; ( f w
E ('67 L
a b m’: / Ii! : (f
a, ﬂ z /
x0 r p 1/ I a? // I a, j
1/: 42 ' Mi 4' Circle instructor: Morrow or Demirov 5 Name:
Lab period: Student Number: [10] 4. (a) A — 3.5 uC charge is located on the x axis of a coordinate system at x = —0.60 m as shown. Point P is located on the y axis such that it is 1.50 m from that charge as
shown. An unknown charge Q is located at the origin. (i) What is the xcomponent of the electric ﬁeld at point P?
A a; , n :6 F #375292 04%))" (7’fm)z x x M a _ (ﬁg 6? I, ; ,éxgjrj/ﬂ C (/AS‘M 7 (ii) It is found that the electric ﬁeld at P has no ycomponent (i.e. Ey =0). What is the
value of the charge Q (Sign and magnitude) at the origin? I” 0 j //Z“""”“ ' 5
AK j’xtl/pw (v. ?7jwr’/f o w 2 U W “J
/a 6? ,{ AA‘K‘Y’W (X, 5/249 (5/ ' WSW) 2 ( / ' m > / L “d 62 V: 3ef/r/0W56 x (70 (iii) What is the force on a 5 uC charge placed at point P? Give your answer in unit
vector notation. is. 3 /‘
CA [We «we/W 4: C
07 .A 3’ Circle instructor: Morrow or Demirov 6 Name: Lab period: Student Number: Some Potentially Useful Formulae and Constants: dzx 62 1 6‘2
2 2 ‘a’zx i] = —2 g}
dt 6x v 6t
F = ~k r x Hooke's Law ~ A
x spring ( ) F12 : k8 r12
E=lkwm x2+v1~mv2 a
2 ‘P g 2 E = k l;
e r2
27?
(o = —T— (angular frequency) M q A
E = i
(02 : ksprmg
m m
vsound = 331 m/s+ 0.6 O X Toe
s. C
(02 =—g— n a
L CDF = jEdA
602 _ $5.0: (D _ qinside
I E ‘ 8
0
k * ~21 (an ular wave number)
— A g V = kg 5].
r
v = fl (wave speed) V = k 8 I v  3 4
[u I/sphere zgﬂ—r3
P = % y VA2 602 (Power : wave on a string) Aspherc = 47rr2 Physical constants: ‘ 1 _ 9 . 2 2
kc—4ﬂ80—899x10 N m /c 6:1.60X1049C 2
80 =8.85><10'12 Cz/N.m2 8:931m/S ...
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This note was uploaded on 03/08/2012 for the course PHYSICS 1051 taught by Professor Michaelmorrow during the Winter '12 term at Memorial University.
 Winter '12
 MichaelMorrow

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