\ta
1013112008
Exam2
Physics105
rl
Name )ott't'4
B
As a student at NJIT I will conduct myself in a professional manner and will comply with the provisions
of the NJIT Academic Honor Code.I also understand that I must subscribe to the following pledge: On
my honor, I pledge that I
have not violated the provisions of the NJIT Academic Honor Code.
Multiple Choice: (15 questions,lpt. each) Identify the letter of the choice that best answers the question.
l.
I
If a firefly collides with the windshield of a fast-moving bus, which statementis correct? l\k-J "t'
L-- t l'/ a a c t T c ^ n
o\n
Ctt
a. The firefly experiencesan impact fbrce with a larger magnitude f\
b. The bus experiencesan impact force with a larger magnitude
fne firefly and bus experienceforces with samemagnitude
@
d. The firefly and bus experienceforces with samedirection
e. None of the above
? r-[
n
f'V*
11@.-).-.
2. When a certainforce is appliedto an object with a massof 2 kg, its accelerationis 10.0m/s2.When the same
force is appliedto a different object, its accelerationis 4.0 m/s'. The massof secondobject is
a.
l.25kg
F=lvr,'
= L"' t\/'
(o
*^(r=
":."F "lgx
b . 8.0kg
10.0kg
d. 2.5kg
A
I w.t
5.0kg
zo^./=lmx +ry 'b^ls
: r*/+ =,
d:,30o,
: , 5 u - , pnd
.a
3 . A block is pushedacrossa horizontal surfaceby the force F with constant velocity. F : 20 N, a
J
+
+7i
:
M l0 kg. What is the magnitudeof the normalforceon theblock?
7i
A ro8N A\",y
Y
cJ
b. 98N
/
.r-
c. 94N
e.20N
7*c6t1^F
,
,^^,,i
Fn t.v : n4 dut
I
d. 88N
= o
s{r.g=
-r 1-- tFl
O.
tFl **e
tir
*\8,l{ -^J
,
,-\,
tt
\rr\r,
|
''rv
O
tt xsnrsc
-- *A t F sru"g '::
"'o { d,f
:= (l "Du ' J':8
- l'l
tx
r
ei
\
'
4 . A heavy weight is supported by two cables that exert tensions of magnitude Tland Z. Which statement is
correct?
',t7
a.
Tt: Tz
b . Tn,: Tt,
o
_.
Tt> Tz
{. T t < T z
e. We need the mass of the box in order to determine the correct answer
(\.
-
(r
LiL
^i t - +U ) T
lL
"' I:jl'T.
2D
) T,>T-
-Fr
Phvsics105
r0/3112008
Exam2
B
Name
in an elevatoris equalto 44 N. What is the
5 . Thetensionin a stringfrom which a 4.0-kgobjectis suspended
acceleration
of theelevator?
"t
,< r r t -A.
? i .
'
F,,"*
t v " t ' t ' ,7 hA
a. um/s2upward
l
l
l
4
T
,^
(9)t'zrnls^upward
i
t
ib
c. l0 m/s'upward
d. t .2rn/s2
downward
e. 2.4m/s2ao*n*urJ
il
I
1 : , -ug--,,r^^
+[tl
t ,
'J '
lm--ae
d'v
i
I
L-.-*J
{ ,, i"
tJ
j
.. 6L= tl--b
fi\^
= ft- -?-r= l r L
A 3.0-kg block slides on a frictionless 20o inclined plane. A force of 16 N acting parallel to the incline and up
of tfre block?
the incline is applied to the block. What is the.aCpele.ration
J
+\.^:
At*1r
a. 3.9 m/s'up the incline
b . 3.9 mls'down the incline
I
?)
Fr*1.{- M (*
n.lSinzo=M Ar.
ld
\ ' l-
2.0 mls2down the incline
)t
2.0 mls2up the incline
,)
e . ).J llvs- up me lncllne
,:0
S* LO
n
-$sTvrzo
" A.r=#
= 1,18
= i6 -?.FxJTvrLo
3
7. ln a game of shuffleboard (played on a horizontal surface),a puck is given an initial speedof 6.0 m/s. It slides a
distanceof 9.0 m before coming to rest. What is the coefficient of kinetic friction beSweenthegrck and the
surrace?
n=elli
r*)'-
K:?l
.r.
v.Lt
i
16 o.zu
d
ry
--;;
0.18
e' 0'13
cL=
"-*t
d
7r: \ Fnt'*)'n
I: 74{'n1
U
d/
n
I '"
['-1';''<
.
i
I
I
tt -
f 3li
*YlE
1ft-ci iu
t('"-t
t
a"T
v
i Al"fK'-ltl = wKx
z4\ (t'-_l-' ' )i U
ft-6t
+--=
\,r'
'
-L'^15 " i
r- i
\
lJ
,
*frrFn,'=rA4*
7-(r/l-vA\r
n " l , u y ' ^ a - n t / n a't. -
8. What is the smallestvalueof the forceF suchthat the 2.0-kgblock will not slidedown the w6tttTtre coeffiiieit
of staticfrictionbetweentheblockandthewall is 0.2.
.
O i*o^
At
d.20N
fr'f i
t*.tlkq.
tne4,X
s).
/r,.
H---+
gesN iF"r-(il=Do.''[F^'l--trl td
'J
=v^qI
At'Y
i
7,t, F*+.? e o
- t't^fl
*t^A
:|
[fr---l
-a rfirtF
Phvsics105
r0/3U2008
Exam2
Name
1.5 kg, what is the tension in the string connectingM and 2M ? Assume that all surfacesare
9. If ,F: 40 N and M:
frictionless.
57
J7 Yqlr't^
'tz,,'t^ i
"
F1of.ett
{tlVtc\
-t Mi =@t (Lftttl)
-^:hok
nr --hrL
uP F^ d^r-
a. 13N
b. 15N
c. 36N
I
-F rt
y\r-{.
eNL,
o
@ zgN
6. 28N
c^-:
c1A
F, a ^:
-FLla
-"Tl-
\
a*
-cgot (.5x?.tr
JK l.l
f f'\" :
F.".,,rt :@ ( Ln ) O\*
z-fr a. €- Ltot tx l.s-;' (-t'6 /
ft
-F+T - 2n 4
TG10. An airplane flies in a horizontal circle of radius 500 m at a speedof 150 m/s. If the plane were to fly in the same
1000 m circle at a speedof 300 m/s, by what factor would its centripetalaccelerationchange?
a.
(b.)
(
d.
e.
4.00
2.00
1.00
0.s0
0.25
z-U2-r.?
4lrt
Lf-
around.
inaclockwise
direction
I r. Aballismoving
"-.,6;;***il
=
LCL
=g
*Yr[,lfn":::ffi#I*-
(a) whEiT[e batfis locatedat thatpoint on the circlg?
directionsof its velocityvector(v-),andacceleration
;--\
t.
r
I
tY
,\
/\
.a
a.
.'--:
al ,'
lr'l
l
'.
rl,
I
,\
xv
tl,
- -rr
-a
fvr'---Il
\
+3-
e
\
t
I
I
\
/1
t'
\
lra
I
I
I
'--
\---l
-a'
b.
e.
9.,
At the bottomof a circulardip of
12. A roller-coastercarhasa massof 500 kg whenfully loadedwith passengers.
radius40 m (asshownin the figure)the carhasa speedof 16 m/s.What is the magnitudeof the forceof the
track on the car at the bottom of the dip?
fu) s.rkN
Y. s.3kN
c. 4.9kN
d. 3.2kN
e. 1.7kN
f?
Al"t 7, F*ri =M^-1
I
l
m \f"rar=*(f)
--w;t*f
{um
: ti,r
16= \
.-.1nr\2x(?.tr+
=*"cJ*H)
+o,
I
= 8(*
Nj'
I
.J
E,r
Physics105
1013u2008
Exam2
Name
13. A 5-kg ball hangs at one end of a string that is attachedto a support on a railroad boxcar. When the boxcar
acceleratesto the right, the rope makes an angle of 30" with the vertical. The accelerationof gravity is 9.8 m/s2
l+',
and air resistanceis negligible. Find the acceleratio4sf the boxcar.
j '(
?D
:: /
*
^ Al,"{i :
a. 56.6m/s'
;' 19, ^/"'
c.
".
V-
'Y
'^.,
17.0mls2 rJ
/^r.s"v"
(
s.l ^t"'
)
.- f\A a.
Kl-i^"t
i ,
7
n
o
,
--^)*
tf lu-Jlo
rJ
l.i,
(
t
\':
a,t,t ot
--a-?c"5 3c'
A-\"gf t F-.*,x=r/rn<-x
l-\ r
htSrur]o
':
l,tt(.x
. \e{T S i n l e
6
/
= (w q r
c,o 5 \ o'"'
ft^2-", : !1tat4lco
bf \c"
Y
^
-A
.'- ^x -d
=?
t-
fxtwtla'=
9-.66
14. If the coefficient of static friction between the tires and road on a rainy day is 0.5, what is the fastestspeedat
whicha carcanmakea turnwith a radiulg{80$meters?Theroadis flat.
J
'1,^
r
Al
3.l'#'*..s''''..ffJJ''-*tx;int-Vn1
. ; , f *r
!\
ir
d. 25 m/s
Fo
J
r-Po;;
*,/
-"'f
r:l^
15.
eil 0.s88
Y-/ o.oo
c. 0.294
d. 60.0
e. 588.0
d
-- vvt
lFuI
\
ar ^./ - i'im"
'flf-*.ry
"
@
^-r'ftg=
".'':;-r,.--
,!,: i-r,.---
FtJn;
,-.-.rtrl=,tfi,1,,,f.=J