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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 &quot;t'
L-- t l'/ a a c t T c ^ n
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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
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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
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b . 8.0kg
10.0kg
d. 2.5kg
A
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5.0kg
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d:,30o,
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3 . A block is pushedacrossa horizontal surfaceby the force F with constant velocity. F : 20 N, a
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M l0 kg. What is the magnitudeof the normalforceon theblock?
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b. 98N
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c. 94N
e.20N
7*c6t1^F
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d. 88N
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4 . A heavy weight is supported by two cables that exert tensions of magnitude Tland Z. Which statement is
correct?
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a.
Tt: Tz
b . Tn,: Tt,
o
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Tt&gt; Tz
{. T t &lt; T z
e. We need the mass of the box in order to determine the correct answer
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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?
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,&lt; r r t -A.
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t v &quot; 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
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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
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+\.^:
At*1r
a. 3.9 m/s'up the incline
b . 3.9 mls'down the incline
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ld
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2.0 mls2down the incline
)t
2.0 mls2up the incline
,)
e . ).J llvs- up me lncllne
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n
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= 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
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.r.
v.Lt
i
16 o.zu
d
ry
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d/
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ft-6t
+--=
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r- i
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*frrFn,'=rA4*
7-(r/l-vA\r
n &quot; 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
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tne4,X
s).
/r,.
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i
7,t, F*+.? e o
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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.
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&quot;
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uP F^ d^r-
a. 13N
b. 15N
c. 36N
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6. 28N
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ft
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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.?
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around.
inaclockwise
direction
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(a) whEiT[e batfis locatedat thatpoint on the circlg?
directionsof its velocityvector(v-),andacceleration
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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?
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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&quot; with the vertical. The accelerationof gravity is 9.8 m/s2
l+',
and air resistanceis negligible. Find the acceleratio4sf the boxcar.
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a. 56.6m/s'
;' 19, ^/&quot;'
c.
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=?
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
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eil 0.s88
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c. 0.294
d. 60.0
e. 588.0
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