ExamI
Physics221,FaLt2007
1. A book is at rest on a desk top. Which of the following forces forms a Newton's third
law pair with the book's weight?
A) The normal force of the table on the book
B) The force of the book on the table
;Q The gravitational force of the earth on the book
( D)The gravitationalforce of the book on the earth
YI None of the above
Utru$f \.{) ft*db]f,r>n+-0
T?r.tf
t1
lD
.|"n* on tML
rr
i,
\
ao*r"t\^ *Y
2. A 65 kg studentis standingin a high speedelevatoras it acceleratesupward with
a: 15 m/s2.What is the magnitudeof the normal force that the floor of the elevator
exertson the student?
A) 338N
B) 637N
c) e75N
D) r274N
@t612N
N ) - cn$ :
N J = on f 6r I
i A
f,c\
3\
= t6tzN)
Qortl^
M4.
Physics221Fall2007ExamI
3. Threeblocksarearrangedon a horizontal,frictionlesstableasshownbelow.If a
forceof 20.0N to the right is appliedto the left mass,whatis the horizontalforceon
the far right mass?
A) 0.606N
,@D.82N
tf,z.q:N
D) r2.2N
E) None of the above
t\^4- ^U-b\a-
fc>t
**p+* j
,D\)
c,6( */r-
6s t\- 34 H'ct
E , n * . ( 3 ob)[o- et r,/*)
(8LN)
into S.I.unitsis:
4. Thespeed150feetlhour (ft/h)converted
/|\
I
A) 4.16 x l0-2 ff/s
B) 5.00 x l0-' in/s
C\ 45.7 mlh
,ta.
nnelevl onJ
eecs"'"A
.
( D)rl.27xl0-- m/s
E) 0.762m/min
rr)+
ry
t+""f
(h
lz io
I iq
\eD ccn
36ros
= | 2)xto-2 -/s
Physics221Fall2007ExamI
is shownbelow. Theobjectstartsat restat x - 0 and/ : 0.
5. An object'sacceleration
Whatis theobject'spositionat timet:3.0 s?
'(Al+.sm
a* (m/sz)
BJ9.0m
C ) 1 2 . 5m
D)15m
E)25m
^--(l
o CI.i
.1r
J
t/l
l
I
I
I
I
I
t
r
\ f - : ' . L + \ " d t= o
)r
r (s)
5.0
*
+ 1 +d t =
Jo
L
j_
2_
Jo
rE r'
) < : X e - + l , f d t - rr
)
O +' - b "
xF.on) i
6
Jo.,
ry *
T
V.5 nn
6 . How long doesthe mass,initially at rest at the top of the incline, take to slide down
the frictionless,inclined plane shown below?
fN
f b
t-Ti
i
t'f<
l l
* l
5 . 0 0m
A) 0.84s
B) l.0l s
s
C )1 . 1 1
D ) 1 . 3 3s
s
ftrD.47
d--
I
2
^'- ?KlnQ= 562*lru
t " nnsslq0
cs-,-b., t,
G
h:!
q t - 1 - ? -- -
ocreler:fiar
dA/r\-a-ff.
F
iA
\iY a'
c6\€/eC
.t t
"l%
d =
i*o\-LR'a5'q) m =
6' lcn
ss)?f
Phvsics221Fall2007 Exam I
7. Two balls are shot toward eachother at the sametime, t : 0 s, off of two identical
tablesthatarel00m apart.Letbatl#l hitthegroundatttandball #zhittheground
att2. If the initial velocity of ball #1 is (Z.Otdr)iandthe initial velocityof ball #2is
(-+.0 tdr)i , what is the ratio of tftz? Ignore friction and air resistanceor drag.
&zu-*n
vl
-?}
-&*re** I
-Tt"a--[i."e-
A)4:l
B)2:l
to1t*
L-s4i.*-t
'D^s- nftairs"^
Fa,rh +
9t',i
E)1:4
ur d^*;-+eJ
a1 :
Gn* ^J
!.st'
i,. flr.r brrre t*, t{t1^, br " tz
8. A flatbedtruck is carryinga 50.0kg box. Boththetruck andbox areat restat a stop
light. Whenthe light turnsgreen,what is the maximumaccelerationthat the truck
canhavethatavoidshavingthebox slip if tttROiPOandpy:0.150?
+r
o
<-
A) 0.98mlsz
B) I .47mlsz
rf;,il3iyfr 1':
cYla-
+'
mlsz
YYYYY+.qo
C UsN):
I
,Ltsnff h
I
'
rnc\
Qrywx=
f.?
= 2,7+-"'l-
Phvsics221Fall2007Exam1
9. A particlemovesalongthepathshownbelowwith constantspeed,passingpoint A
thatpoints
first andpoi$frlast. At whichpoint doestheparticlehavean acceleration
to theright?(!l
Q,=oFt A,B,C,
(*H'u1t[' F"f^)
.
^ ?-n+J 4a^nra
lte-u .er'k; 4 ,
a)J\fftr
L
af
{4
€tc
10. A massis tied to string and undergoesuniform circular motion on a frictionless,
horizontal table. The string will break if its tensionexceeds100 N. Which of the
following statementsis true if the massis 10 kg and the period of the motion is 1.0 s?
'A
(A)fhe
radiusof the circle hasto be lessthan 0.25 m.
B) The radius of the circle has to be greaterthan 0.25 m.
C) The radiusof the circle hasto be lessthan 0.50 m.
D) The radius of the circle has to be greaterthan 0.50 m.
E) Sincethe massis moving with a constantspeed,the radius of the circle can be
anysize.
n r T f
a - (\,7(nbd
T,\'S
I
-l
cnq.
=o'7
fii=o-l
pe'\Dl\t \uON
lG
ff"j
=
J
o
Physics221Fall2007Exam1
of 2.0m/s2as
ll. A workeris loweringa 100kg masswith a downwardacceleration
ropeat thepoint indicatedby the
shownbelow.Whatis thetensionin themassless
asterisk(*)?
I
^f
/
!
d
j
q3--l = nno\
T=
(e -a)
cr1
:BbN
A ) 1 1 8N
0
N
e80
A)
@780 N
D) 4e0N
E) 3e0N
Physics
221FalI2007
Exam1
12. Ariver of width 200m runsfrom thenorthto the southwith a currentof 2.0 m/s. If
you canswimwith a speedof 4.0 m/s (with respecttothe water),whatanglefrom the
eastshouldyou point if you wantto swimdirectlyacrossthe river?
A) 27'
91"
D) 60"
rl-
|
u rt* , st,tDG,
Z.o
3
Qt.y$
+o
()
. & " V)
icre(eaAsl-
13. A particle, moving with constantacceleration,coversthe distancebetweentwo points
that are 200 m apartin 5.0 s. If its speedat the secondpoint is 50 m / s, what was its
speedat the first point?
A) 20 m/s
X=Ko+,Tol +
V+omts
*JD cn =
/@o*r'
D) 50 m/s
E) 80 m/s
'G
I
r t
1-
zo'
(s *)-F L*(a os)
u-. 'G+ o*
5C = T, t
o
@
?rro=
50 --
5i\-J\)O
\)o
K
--Q-)
{-|
e
\
t--
5a-
O,(5.O t)
o,'
5D- \G
a,=, _E__
25D =
5'S"| +/ce-$"\
l-'
fo = %o ,YlI
Physics22lFall2007 ExamI
of a force. Whichpoint (or points)is a
14.Thesketchbelowshowsthex-dependence
stableequilibrium point(s)?
tut
bnu\^/.'F=
S k - a & t q -q,) o
Tr<o
TDo
s
t<o
F><>
+
?
e
\
.^iaBr,
A)A
(F)n
Vc
D)D
E) bothB andD arestableequilibriumpoints.
15.Whatis theanglebetweenvectorI - 3i + 4j - 2k andthex axis?
J
A) 37"
bzz:
,^
Y:
-l A"i
GD
D) 61o
E) 65o
-
CS)
rI
tEll
\--- a
f-r-
lVl * + * + *
=
56"
O
f u t . t tR[r
btu
"dlh
Physics221Fall2007ExamI
of its velocityis 5.0
uniformcircularmotion.Themagnitude
16.Aparticleundergoes
is 10m/s2.Whatis the radiusof the
m/sandthe magnitudeof its radialacceleration
circle?
A) 0.4m
B) 0 . 5m
2 . 0m
2 . 5m
2 . 8m
G a
q
p:
u-z
w
t
\r1\o o4"/j1"
17. Water comesout of a gardenhoseat 10 m/s. The hose,whose end is horizontal and
1.5 m abovethe ground, is aimed atavertical wall located2.0 m away. At what
distancefrom the baseof the wall doesthe water hit the wall?
2 . 0m
A) 0.2m
B) 0.4m
c) 0 . 7m
l.l m
1 . 3m
6
1
r l I
la
l.5cn
7 ;
2 0
s'rt
+o
Xo + \tr"t
:
cY1
D
*f,)+
+ ['O
l- 4tL
Z J
.
f= c,Zs
2
p) {c,a'f:
t
Lfq
Z
I ann
10
Physics221Fall2007Exam1
from rest.When
18.A 1.0kg box is placedon a 2}-mhighpointon a hill andreleased
the bottomof the slope,its speedis 10m/s.Determinethe work done
thebox reaches
by friction.
A) -s0 J
B) -96 J
\
t
D) -196I
E) It cannotbe determined
because
flr.is not given.
€*f
3
m3l^
€ b"ttbrn
5-o
t/.,t4r&rr,, s AE
nrbh: -FF6tl
!-u"-
19. A ball tossedvertically into the air takes2.0 s to come back to the original position.
How high doesthe ball go (aboveits initial position)?Ignore friction and drag.
@;+.q,.n
B/r.sm
c)15m
D)20m
E)25m
A0 I
I i
l:i
I li
t i, a , o , \ t
t\: c>
lvlax h.ue1,ltl",1"
-.)
l,oJ f" WI tb ft* +"p
n
t)e
: .{,r J;t - |lt'
1
d
o
*
,( qa?4(ror)
(ro')- Lr,s}y
= C,1'{e,8?)
rOr)z=
n
Physics221Fall2007Exam1
20' Apendulummadeof a light stringanda smallbob is releasedfrom
theposition
wherethe stringmakesan angleof 30owith respectto the vertical.Right
at the
bottomof the bob'strajectory,the stringsnaps.Whichof the followini
diagrams
correctlydepictsthe velocityof thebobanaifre forcesactingon it rigft
afterthe
stringsnaps?
$:}{ot
l \ i
x)
riu'ltqn&$'l-)
F nr*,nF tz"1\€"f tc Tt*( cr tttirn
*^l*.bq
4
t
a cUcle-,
+t c.*-tr&rl..r*")
A
c
d
t2
Physics22lFall2007 Exam1
r
V
'-"\ \(c-he'{a^^'
n. A{,2.0kg)block slides at constantspeeddown an incline that makes an angle of 30o
What is the coefficient of kinetic friction between the block and
*ihrtdnorizontal.
theincline?
A) 0.22
}tr 0.50
l0
@)0.s8
D1 0.87
E) 0, becausethe speedis constant.
\^
Crupf*r.t sp*J
=> Q=C
^tr'nQ
o
+*=
=o
X,:
U : c\ncusfg- \ )
r!
Pu
[n'
N=+
gr
: NLttrnS
F.
N; ryts?P
= farg = o.TE
22. Aturntable rotatesat 30 rpm (revolutionsper minute) at t:0. Due to friction with the
surfaceunderneathit, it slows down and stopsin 4.0 s. How many turns did it
completein this time?
A\
\{)1.0tums
B) 1.3turns
C) 2.0turns
D) 2.2 turns
E) 3.1turns
t nnt,"l
?pryry
frtn
6os
lCeV
= LDo
: /,lV ne/
/LA : ()%F qt
O =
ql+'F+
Av:tl.,t+
/
\
o { ( q 0 t /)
C{:_o,ltdlr"
l*r'
=(?\L{'+
+ *(-onF Y"os)'
X+or)
= 6 ?s,ad. l*ur*
.-
ffiaJ
-- | O tulw'
r3
Physics
221Fall2007ExamI
23.Thegraphbelowshowsthe potentialenergyof a forceasa functionof x.
Potentialenergy
\
\
I
(-
l\
11
/
o
7
/
\
lsquare:lJxlm
/
\
/
+ + <c
I
/
\
\
il
\
f
s - /
\
7
;
/
x
,
/
\
^/
/
F(
c
\
Rank the x componentof the force (including signs!) associatedwith this potential at
p o i n t xs : - 2 m ) x - - l m a n d x : 5 m
A) I;(-1 m) < F*(1m): F,(5 m)
B) I1(-l m) < F,(1m) < F,(5 m)
C) 4(-l m) < F*(5 m) < F.(2m)
DJ r;(5 m) < F"(1m) < F,(-l m)
,@)None of the above.
V
R..,ro FGZ)) o
trGr)-*.,
r(u\
tr(-4
d *s)(o
t4
Physics221Fall2007ExamI
ropethatmakesan
24.A l0-kg blockis pulledalonga horizontalfloorby amassless
angleof 35oabovethe horizontal.Thetensionin theropeis 100N. Whatis the
magnitudeof the normal force by the floor on thg block?
a\ 'RI\T
A l 9 IN
qU)41
c) 57N
D)e8N
4?
tlL
l| v
T
r-h
t
|
L-4,x
I
r
__r-"-* t- *
E) 120N
\,
,:
C N t-l-rrng
*5 =C
A-
i)
n
U. on5- ldnD
= c+-r
t)
25. Two blocks of massesm and3m arc connectedthrougha massless,ideal stringthat
goesthrough an ideal, masslesspulley in the arrangementshown below. There is no
friction betweenthe blocks and the surfaces.Determinethe tension in the string.-
N
^)l*s
B) mg
a / t aN^ " r l
ffi
c)l*s
D)I*s
$.0"
@u*r
I
ft.?o"
3"b e.n$
T
= d'ilO.-
3^3en?
-
)T3oftot.='
(fcno*
4]:
I
nSq
+?b1
*A
+*a
t5
Phvsics221Fall2007ExamI
The
a springwith k:2000 N/m andis thenreleased.
26.A 1.0-kgblockcompresses
blockthenslidesalonga frictionlesstrackandinto a circularloop of radius
R:50 cm (seefigure).Atthe top of the loop,the normalforce onthe blockbythe
track has a magnitudeequal to twice the weight of the block. How much was the
spring compressedat the beginning?
A) 5.0cm
B) l0 cm
@r13cm
DI zg.Ei 32cm
tot I
Cslele>\6-bf.
=
3qR
J
-1 +l'J a rn-sz
{ *t-r '
V
i-L
l
r
\
-
| z.
ttx
I,L*- Ycnr{L
------.,J
fn
,f;
\) = ?sng, bo
r^s,Th
=
t
1
l / K a
;
B \)q\<t
L
5*ot + "n3zRl ,*
cn
?nn3lt x=\W
= oBcn
t [cKK_
l-
27. A200 gmassis attachedto a spring(k:30 N/m) that is compressed10 cm from its
equilibrium position. If the coefficient of friction betweenthe massand the table is
Itrc:0.50, what is the velocity of the masswhen the spring has expandedby 5.0 cm
by 5.0 cm)?
(i.e. when the spring is only compressed
'o
x . : - 1 0 c m x^: -5.0 cm
/{0.61 m/s
(i'\*z B)X.80m/s
\@
x: 0
€1-- bWl= 'y(wO
#)(or'f
C) l.l m/s
='c.151
D) 1.2 mls
E) Noneof the above
^
l
l
)
=
te avxz +
!-cnsL
(l
.
7 \ -
a [o o,B"T-+ c>'l\r-)l
I
I \-xr\ l , t t c n l ' - O " ' o Y q l
M\ 3 €z-q - v u f a
,
U
c , o a * t+ o ' l f L - o ' 1 5
\r a e.-6D*.fs
* ouovl
t6