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**Unformatted text preview: **Physics 111 Exam 1, Spring 2916 (MC Questions: 2 pts each for a tote}. ofzs pix}
Choose the one letter that: best answers the question and write it on the line to the right. 1. A package falls off a truck that is moving at 30 111/ s. Neglecting air resistance, the horizontal 1. 12
speed of the package just before it hits the ground is
A. zero. B. more than 30 mi 3.
C. less than 30 1'11 / s but more than zero. @W
2. If a car increases its velocity {comm 111} s in 10 seconds, its acceleration is 2. B
A. 60 111/52. (iii/if c. 600 111/52. 11. 3 111/32. --> “-9 D
3. If thex~component of vector P and the x-component of vector Q have equal magnitudes but 3.
opposite signs, and both vectors have identical y—components. Which one of the following statements about these two vectors is correct? “3* "'3‘ . . . . .
A. Vectors P and Q point in opposite directions. B. The magnitude of vector P is twice the magnitude of vector Q .
we ms
C. V t P d l t
so or is perpen ice at o vggtgggwwmwm WWW» -> ~——>~\
D The magnitude of vector P is equal to the magnitude of vector Q W
B. Vector P is parallel to vector Q . 4. The motions of a car and a truck along a straight road are represented by the velocitymtime 4. D
graphs in the figure. The two vehicles are initially alongside each other at timet = 0. At timeT,
What is true about these two vehicles since timet :2 0? Truck 0 T A. The car will have traveled further than the truck.
8 The car will be traveling faster than the truck. Qihettockaseﬂiecmtmaveled the same distance
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D The tiuck wi ll lhave traveled further than the car. ) A. 120 m. @in C. 66 m. D. more an 290 m. wwwéy
S. if a stone felts to the bottom of a mine-shaft in s secondsﬁeqfis depth of the shaft 15 about 5. l l 6 A hockey puck is set in motion across a frozen pond. If ice friction and air resistance are 6.
neglected the force required to keep the puck sliding at constant velocity IS A. equal to its weight divided by its mass. B e oattoatsmas imes its weight.
(2. equal to its weight. I). none of the above ’3 M 7. The equiiiioriurn rule, 21? = 0. applies to
A. objects or systems at rest.
13. ob‘ tones stems in uniform motion in a straight iine.
C. both of these ”I;
D. neither of these 8. When can we be certain that the average velocity of an object is always equal to its
instantaneous velocity?
A. only when the acceieretion is constant
B. only when the acceieration is changing at a constant rate
C. always
D. never @hen the veiocity is constant ‘ of M 9. The force exerted on the tires of a car that directiy accelerate it along a road is exerted by the A. tires.
B. air. C. err ine.
D. rod h‘ E. none of the above 10. Neliie puils with a force of 50 N on a horizontal rope tied to a tree at rest. The, net force on the rope is
A. 58 N and rope tension is 0 N. B. 50 N and rope tension is also 50 N.
C. zero and rope tension is aiso zero. ( gistoandmr 11. Whatmust be true in order for two non—zero vectors to have a dot product and a cross product
with the some magnitudes?
A. The two vectors ggemmﬂeshm
(xﬁﬁmme segwmgted by an mgieifmgﬂ)
C. The two vectors are antiapareitel.
D. Two non-zero vectors can never have a dot product with the same magnitude as their
cross product.
E. The two vectors are perpendicular. 12. While a car travels around a circuiar track at a constant speed, its A. acceieration is zero. 8. velocit ‘ o.
C. inertia is zero. (jg—"ﬁne of tilegisnve 13. Ioshua is attracted toward Earth by a 500~N gravitational force. The Earth is attracted toward Joshua ' h a force of
@ B. 250 N. C. 1000 N. D. zero. 14. A heavy block at rest is suspended by a vertical rose. When. the block accelerates upward by the
rope, the rope tension
A. equals its weight.
B. is less than its w i ht. ' tr th '1: W
. is grea er . snl s Wewr 2. (2/, points) Vectors. Show your work and explain your reasoning.
Consider the vectors AB and. D as shown. g + it — a a 5
y E magnitudes: A = 3.0 Email
[3:32 a. (6 pts) Find the a:- anci y—cornponents of vectors 3, B, and D. AK "a: Q gm? 3?.0 $qu Léaggg 566 pK '3: L20 ,4? == 5o 37 :2 ”3.052s 45”»5‘té 97, (12 pts) Find the magnitude and direction of a vector 6" that wouid make this statement
true: 4+B—C m: D Express your answer for direction (as degrees from the +51" axis toward the +y— —axis): H24 3 5 we 5,: ﬁlm-8f hg=5tg~mozugw r we); =3.0w§.éw ”egg i [3709 + 32.775” 3 .30.). 7S c. (6 pts) The sketch shows the position of the moon at two times, about seven days apart.
The velocity vector for the moon at each of these times is shown. Find the direction of the change
in veiocity of the moon over the time interval between t1 and t2. Indicate the direction by drawing a vector to a simiiar scale as those shown. if the change in velocity is zero, state
that expiicitly. .45. Ah .5
A = V -
{:2 V 3. vi
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Ir” {Vioona’tt2
1”
I
1’ .ﬂ;\\ \ .551
f
‘1
'1 Earth Micaertat‘r1
1 &
VA 3. (24 points) Constant acceleration. Show your work and explain your reasoning.
Beginning with the deﬁnition of acceleration, do
03:1 W T51 derive the equations for 11105) and 33(t ) for constant acceleration 111 the m— direction. In your derivation,
denote the initiei position 31(t —- 0) as $0 and v{t— '— 0) as 21%. (W’riting down the equations £10111 memory
is not adequate for credit 011 this problem.) a. (8 pts) Derive the equation for 111165 ) and identify the constant of integration. )(»emu7ewri
13311111111011 A031 @2111 K} @1111: iiwfi’t .. .
Wee? 15' c1 ? M519 (4111‘; wafﬂe}? ‘ if ' 5331m11’1’e, 11117361211113} b. (8 pts) Derive the equation for Mt ), and identify the constant of integretion. @ X: U; fut+iﬂiytz kc?—
1
11111111311 (:2? 1.1111111111121111 “93131111111111! 1M ”11‘
Sgﬁw’ﬁﬁg 11113611117€1 M11 111% 1311‘"? 11m ”re 5115 c. (8 pts) A cert moves on an inclined, straight track with constant positive ecceieretion. At
time t = 0, 11; has positive velocity at position :1: 2 w2.0 In. Sketch the .17 versus 1‘ 11 versus 1‘ and 0. versus
t graphs for the motion given by this description. 1. "(W7 11 1?me i) N31
M 511113 Constant positive 11cc- oration 1116*
1111111311,;
55V ask-— 1191111: We P1117 P11311111;
JL
1 11111”? 131??
(1111111981: 119111111 5
a WW9 SUWE 1 (A439 1112’ M 11
1 eccebeﬁ; 111*: 1111i) 4. (24 points) Projectiles. Show your work and expiail’l your reasoning. A quarterback throws a pass downﬁeld {which we can call the positive x-direction). The intended re
ceiver doesn’t catch the bell, and it hits the ﬁeld untouched by any player. Assume the football leaves the
quarterbacks hand at a height of 2.3 meters, with an initial velocity of 16.0 m/s directed at 25° above
{the horizontal. Ignore air resistance. a. (10 pts) At what time does the ball reach its maximum height, and what is this maximum
height? Tpmk :: {if :: Iﬁmih '25
3 q‘g ;: Ové? Sac/ﬁg a
Yfeek g ‘7?) a? V0?! Efﬁe}: w :i’jfpmk
== $2.3 +(é.7g)(am veg (MNM‘IV :2 £1: £3 mm b. (10 pies) How far down the field (in meters) does the ball travel hefere hitting the ground? fem.) ‘f’IW £14 £13” 9 ,2 ' “Gag + f? KT’Fd. I
5% Azgjm = Voy'féx-f- 3.31::
ivﬁé‘rﬁﬁk slivaﬁén 3 wlu‘f’fen feefm g (:7. Q? §éwﬁd1§ 92V Q( -
z 63’ at [5 SIA15§
m enf- :2
ﬂ exam?» 3% 4* 0.3g =—* I}. w seam]; Aere'izm‘m.‘ rage; a %$ ff’waf ‘5 060 {595. 256))(1- Qé) 3: 21+, , , wafer")?
c. (4 pts) TWO toy trucks roll off the ends of Identlcal tables. The speeds and masses of the trucks are giver}. Will Truck A be in the air for a longer, a shorter, or the gm? time as Truck
B before it reaches the ﬂoor? Explain. Saw“ free-vice” Whig: 0417 geferﬁs’ m
Aging wé “3"
am: (erefréﬂ ((19% mass m" Aaru'aowfa.’ V) 5. (24 points) Motion equations for nomconstant acceleration. Show your work and explain your reasoning.
A student is toid that the motion of an object is described by the following equation: $(t)2v4m (9—)t+( (2 ELEM? a. (6 pts) What are the equations that describe the object’s veiocity and acceleration at various times? $2 We? to): we? 2: a (if fggﬁ b. (8 pts) Is the initiai acceleration in [email protected] or negative-:2: direction? zit-W; o} s Mmee We; 4“ {mm ,W Magma} WWW . c. (3 pts) Is the initial velocity 1n the positive—am negation direction? we a m d. (5’ pts) is the initial position in the positive-m oﬁegatiﬁ direction from the origin? W if we Wain. if; “5:; {:3 . ”4%”ka
e. (5’ pie) After 3 seconds, is the acceleration in mm or negative direction? hum-”(mev‘ Mats"? a is was eftZWaia a, Mai; f. (3 pts) After 3 seconds, is the velocity in thgggmegative directlon‘?» M “t f“ «s
, , {“23 W .
We) 2; M if c )Ww} m
g. (5’ pts) After 3 seconds, is the position in the positive @mction? ...

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