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Unformatted text preview: EXAM 1
Physics 122
Thursday, September 20th IMPORTANT: This test has 4 multiplechoice questions and 4 problems to be worked out. To assist in grading — please place the answer to each question parting the box
provided. Show your calculations, methods, and approach clearly where possible. Showing
your work will increase your chances of receiving partial credit. You have one hour to work the exam. Use g = 10.0 m/s2 for all problems. Assume all problems have three signiﬁcant
ﬁgures. Talking or looking at a neighbor’s exam will be considered academic dishonesty. N0 scratch sheets or additional paper is allowed on this exam. Use the space provided on
this exam only. DO NOT OPEN THIS TEST UNTIL TOLD TO DO SO! NO CALCULATORS! For Instructors Use only: Problem Score Grader MC 5
6
7
8 PHYS 122 Equation Sheet —— Knight st : Vis + aSAt 1
sf 2 si + VisAt + —aS
2
2 2
st : Vis + 2asAs _. Fet=ma n sz (F net )r=mar=
1‘ st/r
(0sz /dt
Vt=(1)1‘ 27: r_2n T:—
V 0) 0f =9i +(nAt f = 6i + (mm + EL(At)2 2r a V: rg
11:12 Lf = Li 13sz 1X: fo(t)dt
Apx = x
L=rmvt Kf+Uf =Ki +UI
Ug 22gmy Us 2%k(As)2 (A02 = I‘l’lCOZI' AEsys 2 AK + AU + AEth = Wext
Kf + Uf +AEth = Ki + Ui + Wext AK : Wnet : We + Wdiss + Wext
WC 2 ~AU
Wdiss : "'AEth
F = —dU/ds
P : dESys
dt
P = 1:“ V = FvcosG
W = _stds =FAi‘
GmM
Fm on M I 1.2
GM
V = ——————
r
T2 2 47:2 r3
GM
g _ GM
surface r2
2GM
Vescape : *
R
_ GM 2 %
rgeo — 47:2 T
U I _ GMm G = 6.67x10‘11Nm2 /kg2 Multiple Choice: select the best answer; no partial credit. 1)LetE=2i+3j' and F=2i—2}.Findthemagnitudeofé=E+2F.
A) «H? B) 45—1} C) J37 D) 6§+1j :(2i‘+3<\)r2('2'{"23‘) " 20 r33" +43'Llf‘ 1&3ng MHWYHZ‘: V5"? 2) Mary needs to row her boat across a 200—mwide river that is ﬂowing to the west at a
speed of 1.0 m/s. Mary can row the boat with a speed of 4.0 m/s relative to the water. If
Mary rows straight north, how far downstream will she land? 9 1:?
X
200 /\ m .
333?: 311323 N Ali/LT” b
(ﬁzgfrl—Q/obE‘r VMO X32ézi—Uojc1VMO
Root/name (a : urn/«sea
E; 505 ” “som 3) If the acceleration of a particle is zero, its velocity must also be zero.
3; A Particle mow“ n Lgin an 7
non— acre 5 ve\oc ‘4 has '26er CKCCC kamiicm ( Qé’nélqﬂl ) 3‘1? W 4) A child slides 5 meters down the surface of an icy slide. The top of the slide is 3
meters above the surface of the level ground. What is the component of the child’s
acceleration along the slide? a. 3/5m/s2 b. 4/5m/s2 3 (9“ 3% c. 6m/52 5‘“ ’ a m '2.
d. 8m/32 be Is Worked out problems. Please show all work. Place your answers in the box
provided. 5. A woman stands at the edge of a cliff, holding one ball in each hand. Simultaneously, she throws one ball straight up with speed 10.0 m/s and the other straight down, with
speed10.0 rn/s. Use g = 10.0 m/sz. a) Which ball has the greater acceleration at the instant of release? b) Which ball has the greater speed at the instant of release? both ba\\s have ONLFC’TVEF‘JF Velocities bur hoof WC] 579666; 0) Which ball hits the ground with greater speed? both ba\\$ hit w‘xl’h 'H/lﬂ Spccpd (1) Assuming the ball that is thrown downward strikes the ground 2 seconds after it is
thrown, at what height was the ball when released? m/ if}
L3: ~30 evoth + lgcujjg?’ (3)0 5
\ m 2 :2
0: 5o» IBM/3(Zs\~z[\0 @2305) e 5
“:BOZQLOMJrZOmrqor“ “1% HOW» 6. A hot air balloon is traveling vertically upward at a constant speed of 4.00 m/s. When Ll mi: it is 1953\m above the ground, apackage is released from the balloon. Use g = 10.0 m/sz.
AR a. For how long after it is released is the package in the air? 0
\ 03K V‘s“? 1 “Bi + 0 3J5 V3102: v51?“ + 2a 053.32%,
V I i Z _ m 2 ﬂaw x 2 V5; VSL V j; : GYM/S) +2( )0 BY ®
,. 0 t .M 5
\ a5 : W+38Llrlémo
x/
m i M 2 20 "Vs
m iOm/SZ
fl: ‘3
‘ t 9 H95
l» as b. What is the velocity of the package just before impact with the ground? 36,: work aha UC 6&0 “v5 7. A lamp hangs vertically from a cord in a descending elevator. In coming to a stop, the
elevator decreases its speed at a rate of 2.00 m/s2 and the tension in the cord is 108 N.
Use g = 10.0 III/$2. a) Draw the ﬁee body diagram of the system: b) Using Newton’s second law, ﬁnd the mass of the lamp. 8. A 6.00 kg weight is connected by a string over a pulley
to a 2.00 kg block that is sliding”? a at table as shown.
The direction of the motion oﬂ‘block is downward and
the coefﬁcient of ﬁiction between the 2.00 kg block and
the table is 0.200. Use g = 10.0 III/$2. a) Draw a free body diagram for each mass. “T’~MN Z mcx i’ (Goff? 0‘ c) Find the magnitude of acceleration for the blocks. 8:75 wrlrb ...
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This note was uploaded on 04/17/2008 for the course PHYSICS 122 taught by Professor Pope during the Spring '08 term at Clemson.
 Spring '08
 pope

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