General Physics II (PHYS 104)
Exam 1: February 23,2012
Name:
Multiple Choice (4 points each): Answer the following multiple choice questions. Clearly circle
the response (or responses) that provides the best answer to the question. If you desire, neatly
and briefly show any calculations or reasoning off to the side. This work may be considered in
the evaluation of the exam.
1) The distance befween the crest of a water wave and the next trough is 2 m.
a particular wave is 2Hz, what is the speed of the wave?
A=,lrr
tA/^
$ *' ##a
'*rrn
/
a) 1m/s
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(
c)4mls
O Not enough information given.
If the frequency of
,*;.{
\tr-,
oor \lF
f,/t
F.
2)
I
of 0.40 kg, hanging from a spring with a spring constant of 80.0 N/m, is set into an
up-and-down simple harmonic motion. If the mass is displaced from equilibrium by 0.10 m
and released from rest, what is its speed when moving through the equilibrium point?
A
rnass
b)
0.0
tt
d)3.4
v
K
_*
rn
A*
x
,W.(.1*i
'l rYkfu
/=
'
3) The sound intensity level of a jet plane going down the runway as observed from a certain
location is 105 dB. What is the intensity of the sound at this location?
a)3.54,.
c) 8.25 x
e) 1.05 x
fr:
v
:l
b\2.45 x 10-2 Wlmz
10*3 Wlm2
10-3 Wm2
10-2 Wlm2
lt-)
i:
f63.ro " 1o-2 w/m2
,1t !
$- :;
t''t.,.
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i"t
if
l;-' :':" f {.'!
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.
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f'e-S
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i#
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4) When two tuning forks are sounded at the same time, a beat frequency of 5 Hz occurs. If one
of the tuning forks has a frequency of 245 Hz, what is the frequency of the other tuning fork?
(There may be more than one correct answer.)
a)242.5H2
c) 247 .5 Hz
G\z+o H,
GDso H,
Page
1
5) If
an object of mass m attachedto a light spring is replaced by one of mass 9m,the frequency
of the vibrating system changes by what multiplicative factor?
a)
3.0
b)
L) = L,
il"
6.0
r**, ,lllr
-'7 :td ftlr-
r*
,ly.
v
f-{ct,
+-
rh
f"rn = k
-2
^ ff *' 'i'p"M
r,
c) 9.0
")W
t/x
I
-+
,
t;.. "i,i
-:r-,bfr
lt
q
* .*' lt' i
#il'
f,*'
'.\ -..,- -tlr: :'" ,':"'i!
--4 f
+3.2
pC.Howmanyelectronsmustbeaddedto
of
6) Analuminumnailhasanexcesscharge
the nail,to._zukg it electrically neutral?
e) 5.0 x 10-14
b)3.2x 10-6
\.lFG@'*Tfi'
d) 3.2x 106
c) 2.0 x 10''
'
c
ffi
F*AN
U? e
s
ArV
=?
Two uncharged conducting spheres, A and B, are suspended from insulating threads so that
they touch each other. While a negatively charged rod is held near, but not touching sphere
A, the two spheres are separated. How will the spheres be charged, if at all?
Sphere
a)0
A
b)
SphereB
+
+
c)0
0
d)
0
@+
'h
l1
q
tl
frx4
f-
8)
A very small ball has a mass of 5.0 x10-3 kg and a charge of 4.0 pC. What magnitude electric
field directed upward will balance the weight of the ball?
q- H *&iis
{Js
l"*
Iffi
a) 8.2 x102 N/C
r-** fi?
c) 2.0 xl0-2 N/C
e) 5.t xt06 N/C
l--
%
a 6 pC charge. What is the maguitude and
direction of the electrostatic force on the positive charge?
c) 4.8 N to the right
d) 4.8 N to the left
6
I Q,*
U
S: f,xi d.i ?,7??
r"****""'.-**/
A -4.0 pC charge is located 0.30 m to the left of
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,,
Kd'"Fil
f
r.*'-
v*?
F
9)
sl
E,?d,,r
trs i (
IW
(^
pparye2
e) 7.2 N to the right
,*&
f<x',t ?
*{*'
a
6-e ds C
/ 1fl A
{ o *a-''
ffi
qn
* ?r*
10) At which point (or points) is the electric field zero lJ/C for the two point charges shown on
the.x
axis?
+4q
$f
-2q
-#l;
=;f
.l o **
f+{h,-*e
ti'
x
a) The electric field is never zero inthe vicinity of these charges.
b) The electric field is zero somewhere on the x axis to the left of the +4q charge.
ffrffr. electric field is zero somewhere on the x axis to the right of the -2q charge.
Tfn" electric field is zero somewhere on the x axis between the two charges, but this
e)
point is nearer to the -2q charge.
The electric field is zero at two points along the x axis; one such point is to the right
of the -2q charge and the other is to the left of the +4q charge.
Questions and Problems: Provide clear and logical answers to questions 1 and 2 rydeither
question 3 or 4. Where calculations are required, neatly show all work. You must clearly show
all work to receive fu1l credit. Be sure that your answers have the correct units. If you continue
your work on another sheet of paper, be sure that it is clearly labeled. Be sure to include FB and
other diagrams where appropriate,
A/r1 d
/
A block oscillates on a spring with a spring constant of 20 N/m
energy
of the block as it passes through equilibrium is 25'0 J.
The kinetic
1 (20 Points)
a
period of 3.0
s.
a) Determine the frequency of the oscillation.
b) Determine the mass of the block.
c) Find the maximum speed of the block during the oscillation.
d) What is the amplitude of the oscillation?
e) What is the maximum acceleration of the block?
f) Describe the relationship between velocity and acceleration during on complete oscillation.
&)./\ntl J-, - Jr\
*DJ
e)
30,
,YIY
cAll
<*
m=
V,
.*=-*
{n
l-
vVF=
,iriaX 4,rnvd
116/
d
'
r\
,/*
---,.
{= t}?
,-.^,i.>\,-'
Lflfh
#"w#/M
.
= KFrr*, t lJgror= hUU*
d)
f
d
T= *\r
CW= * Vyn {:t
Page 3
3,)N/r^-(,56
L
4 fi
.,!;r
I
rlv "l{-p-,{
{o fg
--
--rr
It),tll
I
ft- \ 9{,r r,rr
l
--ls8n
----a
'l
vb
t<
5,t
t
ilr
't';tr
lr7
*.ST nr
.r r')=
* D^ \4!t
I)
f,1
!',
Jdq
."
1r,= I
n9
placed
2 (20 points) Four point charges are
at the corners of a square as shown in the
figure. Each side of the square has length
m. Determine the magnitude of the
field at the center of the square. The point
at the center of the square is a distanc e
m from each of the four
lie
*r
A
2.0
electric
P
1.414
corners.
L
'
VA
( 5
\y fi
+\
k== AfrC O
=
*l nc
D
@
- ftr, = -e n C
a) For each of the four charges on the corners, draw a vector representing the eiectric fie1d at the
center of the square.
b) For each charge calculate the magnitude of the electric field it produces at the center of the
{
square.
4
cjlete.-ine
the magnitude of the total electric field at the center of the square. In what direction
is the electric field pointing
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ve
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Es
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c)
+rq Nt^
=
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l=\ai=
2
lf,
_ 6,?q /y/c
I
F^+ €= :
->
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->
-5
I=-
F, tL+
Ss"'n' (
5 o,* o 'ttac,"Ya'fuJ'{
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tle
-X
r-=
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Eru
^t
13,'/tr N1,
\
A
-->
A 'l{ =En
ryt D -vs'
= 3.'t8
a^rle
lrettzrfu?J
,/
fr
Wl'f
!
bt l{ + f ,rag trf =
l3,,ty N4 ros V{
+ 17,Vff *Los Vf *
Page 4
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Aii
3 (20 points) A guitar sking with a linear density of 2.0 grn/mis stretched between supports that
are 60 cm apart. The speed of the wave in the string is measured to be 16.8 m/s.
a) Find the tension
in the string?
b) If a standing wave forms when the string is vibrating with a frequency of 840'Hz, how
many antinodes are observed?
F'
, -1"
rI
t-
/=
/,1
t-
'T
\/= At
A:
'/+ =
1.6,T
4t
Kva tta.
-3
Xto
vA4 ={/d {,K)2 2
bfn
,5 6tl- N
= ,oJ
42L
/to
. a24"
^
Page 5
14
4 (20 ponts) A sound meter located 2.0 mfrom a loud speaker measures an intensity of 2.0x10-a
Wlm2.
a) Determine the power output of the loud speaker.
b) Find the intensity measured by the sound meter when it is located 8.0 m from the source.
c) Determine and compare the sound intensity level (in decibels) at the two locations.
L)
n
ul
\t#&y,iil*Ninb
/.-----)
-
aot'
+
-l'
?
*
,frlrr*
P _
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YII l::= :
+
.&
*/n*
n/*m
)*
(inf,vtz
;u !lI)- Y| "
sxl
L.
| = , Ol ooSW E
b) rr l,* * r- tl,iy *
:r-4' -- #'
rr *: ,+fT
gxtiq4rn*
W
c)
&,* l$ $r;ry J7;;
oa
=
* ls J*b se1& -
lo l
l,Af xl;'o^
f*f
=
$m)t
-y4A
N tA*+
urt/n*
' ({ ty, tCI41vlne)
U
B3
7t
ls
Page 6