Exam 1 on SEP.20.2016- Physics105-R. Schad
YOURNAME
Keepthis questionsheetfor lateruse!
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Mark the E
This is to identifr the examversionyou have- IMPORTANT
Mark the C
Whenyou throw a ball up in the air, during the motion ( choosethe right answer)
a) The accelerationis maximum when its coming down
b) The accelerationis constant
c) The accelerationis minimum at the top
d) The accelerationis maximum at the top
Rankthe tensionin
the stringsfor the 3
cases!
lt
8tr
To>Tc>Te
Ta>Te>Tc
Tc>Ts>TA
Tn>Tc>Ta
Tc >Te>Te
,+
5.
The velocity of an object as a function oftime is shown in the graphbelow.
/-
I
\u)
b)
c)
d)
e)
z_
L--+>
-t
Which graphbestrepresentsthe net force versustime relationshipfor this object?
tt,o,^/t+(B)
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1('r
|
lf*lJ--418*
Y6
-a
1p)
| '-
1Fl
l-
I
|
You accelerateyour car with a constantaccelerationover a distanceof 400 m in l0
6.(
C,
seconds.
The acceleration is:
a) 0.4m/*
b\ 2m/s2
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n/ :
t'
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2*
el 4,
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av
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I
10
J
A constant force of 12 N acts on a 3 kg mass [initially at rest].
At which time does the mass reach a velocity of l0 m/ s?
q
a)
b)
c)
d)
e)
clL
8.
2 <x
d) 4m/s2
e) | m/*
fi
I
.q/ +7r'
& = ------
@ t */r'
7.
nv _
'
40s
0.83s
2.5s
3.5s
None of these
F- rhol
=.>iF'=
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v/ = l/'; t
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tu)
7 2r,
4L
A football is thrown with someinitial speedat angleof 45owith respectto the horizon.
Its speedat its maximumelevationis 10 m/s.
What was the initial speed[speed: magnitudeof velocity]?
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t-
to ?,
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a) 10m/s
b) zero
@ t+.t .lt
d) 20 m/s
e) noneofthese
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9.
ft
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4
A ball is thrown in the air at angle300and follows
the trajectory (A is the startingpoint) as is shown in
fig (right). Which of the following is true?
a. It travels slowestat point B
b. It travels fastestat point B
c. It travels slowestat point A and C
d. It travelswith constantvelocity throughoutthe whole trajectory
1{t
10.
I-
I
11.
tI-..-'
ThetensionT andtheweightsof thetwo masses
mustbelike:
a)
b)
c)
d)
e)
m2g> mrg >T
T>mrg>m2g
T>mzg>mrg
mrg>T>mzg
mzg>T>mrg
Rank the velocities(not just
magnitudeobut like: +2 > -5) at
t : 5 s n1 0s , 1 5s r2 0 s
a)
b)
c)
d)
e)
vs : vto : vl5 : Y2o
vs : Vlo ) Vts ) Vzo
vrs = vto ) v2o> vs
u* ) vro ) vrs > vzo
vrs: vto ) vs ) vzo
QI
Rank the velocities (not just magnitude,
but like: +2> -5\ at
t=1sr3sr6s
a)
b)
c)
d)
e)
vr: v3 = v6
vrlvl)ve
vr )velvl
vr:v6)v3
velvs)vr
Vu=Vr
il
L3.
In a local bar, a customerslidesan empty beermug down the counterfor a refill.
The bartenderis momentarilydistractedand doesnot seethe mug, which slides
off the counter.
What is the influenceof the initial horizontalspeed?
I
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?r
t4.
I
c(
a) The fasterthe initial horizontal speed,the faster it hits ground.
b) The slowerthe initial horizontal speed,the fasterit hits ground.
c) The initial horizontalspeedhasno influenceon how fast the mug hits
ground.
An elephantand a teenagerare
having a tug of war. The actionreactionpair for the friction force
exertedon the teenageris
--.'r
*
{1
15.
r
5]
a)
b)
c)
d)
e)
the force the elephantexertson the teenager
the force the teenagerexertson the elephant
the horizontalforce exertedby the teenageron the ground
the horizontalforce exertedby the groundon the teenager
the friction forceexertedby the groundon the elephant
If an object started from rest and
is undergoiog un acceleration
varying as shown.
At which time(s) would it have a
negativevelocity?
lgruph showsaccelerationin
mf szas a function of time in sl
1.
2.
3.
4.
5.
At L second
At 2 seconds
At 3 seconds
At 4 seconds
None of these
15
-a*-*-'-"*-
l"L
o.t
0
s$
L6.
u
a\
Two balls are thrown off a building
with a straight horizorrtal initial velocity of
15 m/s and 100m/s respectively.
lA/hich one will hit the level ground first?
1.
2.
3.
4.
cao
g
17.
The L5 m/s ball
The 100m/s ball
They will never come down
Both at the sametime
The horizontal surfaceon which the objectsslide is frictionless.
The left massis 2 kg, the right 4 kg and the magnitude of the force F with which yotr
push the big block is 4.5 N,
determine the force the small block is exerting on the large block.
tmks'Yl?n&
|
4.5N
1.5N
9.8N
3.0N
zeto
a.
@
c.
5?
L8.
d.
e.
r-
F.,-lH.a
{fra
F
If a rocket would flv
agc()rqrng It) ule rouowrng
D
graph, showing its
vertical acceleration [in ny'szl
as a function of time [in
units of sl When would it reachthe
highest point?
1.. 0s
2. 2s
4r
3. 4s
4. 5s
r\
I51 6s
\,/'
'
2
t
,t
Y-*
t
/'
E -Fr, = 4Ha
=4f/"
rgt
=F
^.
-:a -6n
'
Ir
lFrJ=lEr/
19.
If a car is travelingnorthwardand speedingup,
what is the directionof the accelerationon the car?
(,
l;ilF
20.
?
1.
2.
@.
4.
5.
2'J..
-A
-i/
I
southward
eastward
northward
westward
neitherof these
A personpulls a block [weightW] acrossa
rough horizontalsurface[friction force k] at a
constantspeedby applyinga forceF. The
arrows in the diagramcorrectly indicatethe
directions,but not necessarily
the magnitudes
of
the variousforceson the block. Which of the
following relationsamongthe force magnitudes
W, k, N andF must be true?
a) F>kandN:W
b) F:kandN:W
.g) F:kandN>W
#F
A t./
d
Al
( g gr > k a n d N < w
e) noneofthe abovechoices
A student[mass:65 kg] standingin an elevator
which is acceleratinsdownwardwith 2 m/s2
is exerting a force on the elevatorfloor of magnitude:
[g:9.8 m/s2downward]
It ^l(P1l '
rl
22.
u
r*,il --t
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*h-
f*.'
a) Zero
b ) 1 9 . 6N
c) 637N
' r'*J
.t-
@ sotN
e) Noneof these
f i t,2t A, r-
, fl \,
r' F - _ f
dr.(p -,,V
lvi r'
zl
twz e
A 20-kg block on a level surfaceis pulled atby a l2-N forcethat is directed30" above
the horizon. The coefficientof friction betweenthe block and the surfaceis 0.3.
The strengthof the friction force is:
a)
b)
c)
d)
e)
52.8N
12N
58.8N
10.4N
3 . 1N
f\
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ry-
rrQ = F*or,r-
'4.-
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6niZonA(
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t/
9
A block first restssomewhereon a horizontaltable.
Suddenlyit receivesa short hit in the negativex-direction.
Under the influenceof friction it graduallycomesto rest again.
Which of the following graphsqualitativelycolrespondsto the scenariodescribed?
The graphsall show position as a function of time.
|'t
a
tt
a
,,t
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t.'
I
c.t
o
"r {L*-r*^*r*,
*l-r-*-.*-"r.-)
- x 6lm'/oo'
A block M = 3.0kgl is prrshed up a frictionless 30oincline by * applied force as
shown at a constant velocitv.
T
What is the magnitude of the applied forcp!
NN
F
F
fx
lq
T
17N
29.4N
25.5N
14.7N
none of these
a.
b.
c.
d.
e.
n
t-/\ X
*0
O _q*r J
G;/
zl" J^f
@,/*,,"
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=0
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:
F
Lr" q
= t'ntr h,4
'e Ctt>
*a.!-
"f
velocity
acceleration
gravitationalacceleration
Kinematics
(l-dimensional)
v: dx/dt
a: dv/dt
a: g:9.8 m/s2downwards
vr= vi * a't
xf:xi*vi't*Yta'(
v? : vi2+ 2a.(xr- xi)
ProjectileMotion
(2-dimensional)
Vxf:
Vyf:Vyi+a't
Vxi
Xf:xi*vxi.t
vy?:vy?+2ay'(yr-yi)
yf:yi*vyi't+%'a'(
Newton's Law
F=m'a
Frz= - Fzr
[action/ reactionin oppositedirections]
Friction
Ffriction: Fu p
Radial Forcefor circularmotion
Fradial= mV'/f
quadraticequationx'* px * q:0
xt.z: -p/Zt(p2/+- q)tD