midterm1_wi11 grinstein

midterm1_wi11 grinstein - Physics 2A, Sec X00: Mechanics --...

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Unformatted text preview: Physics 2A, Sec X00: Mechanics -- Winter 2011 Instructor: B. Grinstein Mid Term #1 INSTRUCTIONS: Use a pencil #2 to fill your scantron. Write your code number and bubble it in under "EXAM NUMBER;" an entry in error will result in an automatic 10% deduction. Bubble in the quiz form (see letter A--D at bottom of page) in your scantron under "TEST FORM;" an error entering the "test form" will result in automatic 20% deductions, and may lead to disqualification. Write your name and 3-digit ID at the bottom of this page and turn it in with your scantron when you are finished working on the exam. 1) The plot below shows the position of an object as a function of time. The letters H-L represent particular moments of time. At which moment in time is the speed of the object the highest? {(0 Pnsiliun A)L B)I @ D)K E)H Spud 7-. m magnihde ac Vdochlgo an CM mm; or," quad an a Pod-Hon us. me. amph as m ls'tcepnecsl: or 4“ absolwle. value «F m slope.‘11w 3m?» «Wears $+¢efes+ 4+ Mc 3’ (desfik €32H=1§<o, when: Wis brat)- Sohd'iofl’ by Be‘qn She-hue” (bshotwelléucsdmo/u) Name KEY Student 3—digitID version—page: 1 2) Bob and Biff throw identical rocks off a tall building at the same time. Bob throws his rock straight downward. Biff throws his rock downward and outward such that the angle between the initial velocity of the rock and the horizontal is 30 degrees. Biff throws the rock with a speed twice that of Bob's rock. Which rock hits the ground first (assume the ground near the building is flat)? A) Bob's rock B) Biff's rock C) They hit at e same time. D) Impossible to determine f.” '30? Jvousg w?» 3.4? i? by, we? 50b 9V0 ’gfitlolma -» fir—v ‘-‘--—3"’“"\“ I (MiKCA ’fit' carCOMPOde' 0? 39b; Pock"/‘ Velodth V¢c+or is —v. / ’fiic 1vwmponm+ n? 394'; rack'IA veloc'N-Y vus‘or is —n’>v, sin 3C')"=..Vo Balm races haue Hg $41M g'meonaM' as «up mum wink, wckrs/ W 50'“! fluff pro.” m 5“; loce+ion 4+ 1‘: $4.4m Me,m&g’ 50% racy. hi‘ it; around 4+ 1!. Me. Me. version-page: 2 3) A ball is tossed vertically upward. When it reaches its highest point (before falling back downward), A) the velocity is zero, the acceleration is zero, and the force of gravity acting on the ball is directed downward. the velocity is zero, the acceleration is directed downward, and the force of gravity acting on the ball is directed downward. C) the velocity is zero, the acceleration is zero, and the force of gravity acting on the ball is zero. D) None of the above when 4k. ball reaches H—b QP¢K,'1+ i511"! new? ,and 3. +9. Va“)? “.5 ZCIO.A 41-94-»ng diolacm 0.? ‘HQ loqu 4+ fl}, rpmfv tooqu 0417 hue One, Greg new: cw ‘f‘v. bull'- ‘Hv. acqulhffmq! ‘FOftc Qd'ma chflwafd. pom gau‘: #1:, yaw: lg/e-Pv" Lg’amg we know 444% W) ode Come. will ram/e 4" accelerafiod ‘m ‘4“ 3m oart cm ‘ ’ 1’ A t“ CH“ WA ward4_ version-page: 3 4) Bill and Susan are both standing on identical skateboards (with really good ball bearings, so you may neglect friction), initially at rest. Bill weighs three times as much as Susan. Bill pushes horizontally on Susan's back, causing Susan to start moving away from Bill. Immediately after Bill stops pushing, A) Susan is moving away from Bill, and Bill is stationary. B) Susan and Bill are moving away from each other, with equal speeds. @usan and Bill are moving away from each other, and Susan's speed is three times that of Bill. D) Susan and Bill are moving away from each other, and Susan's speed is a third that of Bill. Nana’s 3"!4134» {ac/s 'lhwl' «allot-ever fire; Susan Fuel: Q‘om Bill, 13;” receives q are; {tom 5mm .c :7“! martilv-lc and Opp-We ‘Grcdr‘M. ‘flwt'v, lu‘h people Qre 0300:": may 'Gom and. m’amd «Hau- onc. is staliwcuy. +3; .- _, d +¥ .- J ._I Aka £Ef=ma=mgiL d Sk<£g+>d€= m54.dv=MAv ( fir my me. 4; eflhfs], 4a, c...“ 4w 5...“ cats 9.... gm 7; m {m maaa'vhule, as #9. 4m; 44;“, '3'.“ twelve) QM mum. .b 11"“ lmam A21“: lmaumb‘fuml / or lAQMMl= Blink”) 5) A 23 kg mass is connected to a nail on a frictionless table by a (massless) string of length 1.3 m. If the tension in the string is 51 N while the mass moves uniformly on a circle on the table, how long does it take for the mass to make one complete revolution? A) 4.5 s B) 5.2 s C) 3.8 s D) 4.8 s N 466‘ "No (464. 40‘3"! 75 in Care; l «v.23 fl = ‘l' _ _ M -,/" P .PI’OVIJMa ‘lN. Cult-P 46¢. ' / r‘l03M = 1'4"" —- ~D‘rr m 300’ 9 V We. - f / [6" + ‘c F, / r, 4% We at Item/«Hm T- My: _, (airfmr ,, £_ mc (95230-30 r is " Dfm -r' “ 1911’ (5., N) = 4.35“ version-page: 4 6) A boy throws a rock with an initial velocity of 2.15 m/ s at 30.0° above the horizontal. How long does it take for the rock to reach the maximum height of its trajectory? El L, a A) 0.215 s B) 0.303 s D) 0.194 s Faint, o-P MdeWYI what-e V = 0 .2 «fl 6 Luggage 30499 V - _ Vac-59 £3 ‘- Vo’? + at 0: Voshg {- ___. VgsMO __ (&.r5'm3n\«,30° _ 3 "' (q‘8%a) "' 0.”:ec. version-page: 5 \\\\\\\\ 7) Block A of mass 6 kg and block X are attached to a rope which passes over a pulley,as indicated in the figure above. A 50 N force is applied horizontally to block A, keeping it in contact with a rough vertical face. The coefficients of static and kinetic friction are _u5 = 0.40 and pk = 0.30. The pulley is light and frictionless. The mass of block X is set so that block A is on the verge of slipping upward. The mass of block X is closest to: A) 7.6 kg B) 8.5 kg C) 7.2 kg D) 6.8 kg m .14" block A i) all ‘h Verge °¢ sipping KPwafJ, 00¢ RMHJW 5}; =/(,N and M! "f‘t‘s Gic‘kml Greg, 7: direckol ’(Dwdwalds, T ' N = P x '1' T = $3, + MA mx . .— 3 \2 mg - Aim mag 14», ‘ —r=mx3 MX=MA+ L3? " 3 may.» " 8' O 3 N'“ all any, (MCGI $0! each Ob'aed' Dec-own “L spam is (5..“ bule m ezambuun, version—page: 6 8) A particle is moving clockwise in a circle of radius 1 m about the origin of an x-y frame. If it completes 3 revolutions in 211 seconds, starting at t = 0 from the positive y-axis, the functional time dependence, with t in seconds, of the y-component of the velocity vector (in m/s) is given by A)3cos(3t) B) sin(3t) D)-cos(3t) E) cos(3t) 3: (1m) «95)::3-6] ‘ Mr“) W'- flapflvde my kc Mud-OI, five. 4% is 1". rec/ft". \ Maw use. because we wé g: auxg'lm q+ {:0 we NM? 3 rev-Idiom '4' 4’11“ SchI.‘Th¢$"(‘p w; haw; Oosfwéj, an M +9 c7“! 5-"- (41‘ an,“ at 3rwr) :> “:3 V3: ’31- : (3 "/9>(-5'm f3fj) , or clw'u C 9) A particle is moving clockwise in a circle of radius 1 m about the origin of an x-y frame. If it completes 3 revolutions in 211 seconds, starting at t = 0 from the positive y—axis, the functional time dependence, with t in seconds, of the y-component of the acceleration vector (in m/sz) is given by A) - 9 sin(3t) B -cos(3t FO" 4“ M @9903 as above.’ D) cos!3t! g: ('0‘) 0°! [3*] E) sin(3t) Va: 5%: = (— 37,) ‘3de] dz = %—= (_fi%a>a$[3€1 version—page: 7 10) A particle is moving clockwise in a circle of radius 1 m about the origin of an x-y frame. If it completes 3 revolutions in 27: seconds, starting at t = 0 from the positive y—axis, the functional time dependence, with t in seconds, of the x—component of the acceleration vector (in m/s2) is given by B) - cos(3t) x = (M86530 C) cos(3t) D —9 3t Elsin(c3(:)5( ) WW? l2“‘°“ 4’ (m “*4 13*? are rm in 9mb.*8 39/4. fins? use. Rem: an wmf k: o 0% int). 480, whm { 5 f (Sane drmellY small, "ghee dumber), Let M X +0 5: {7052+in since 4“ Md: 7, mm: clockufise ’Gom (fig): (0(Im3' («a I’MZBEJ 42:- 3€>0/ 9° We. signs an, emu, Md +,M[.~:{ detains M X'Mo‘bu 94‘ We Parflclg flue-6'2, version-page: 8 11) The x— and y—coordinates of a particle in motion, as functions of time t, are given by: x=4t2-3t+6 y=2t3-3t2-12t—8 At the instant the x—component of velocity is equal to zero, the y-component of the acceleration is closest to: 2:;27‘7/32 x= WE’- 3++é . m S C)-15m/s2 Vx= gt _ 3 = o D)-10m/s2 —"\/,.=o “Jun 6:37g g: .98- 3t°- we 8 v3: 669— 619— :2 a3: lat -b (Wu/,3 = tat-5‘ -é = (—I-g) Allqul-v'ha' an. in 5; Wm, r- 43-— -/-5"/,° “A... vx=ox rt version-page: 9 12) A projectile is fired at time t = 0.05, from point 0 at the edge of a cliff, with initial velocity components of vox = 80 m/ s and v0y = 600 m/ s. The projectile rises, then falls into the sea at point P. The time of flight of the projectile is 150.0 s. vox = 80 m/s v0 voy = 600 m/s 3’ P (— n —> The magnitude of the veloci at fime t = 15.0 s is closest to: A) 747m/s W C) 455m/s D)751m/s E)453m/s Vx = V0"c = 80% (no accelerq-fioa ,4 ’Q,o(;~c+,-ofl\ V3: V0, + q+ = 6,0075 ' 3 (’9'0m> = 453% 3 Nil: {imamfimsmg = lacy, A». version—page: 10 13) A projectile is fired at time t = 0.03, from point 0 at the edge of a cliff, with initial velocity components of vox = 40 m/ s and voy = 800 m/ s. The projectile rises, then falls into the sea at point P. The time of flight of the projectile is 200.0 s. Vox = v0 voy = 800 m/s Y P <— D —) The x—coordinate of the projectile when its y-component of velocity equals 640 m / s is closest to: A) 560 m B) 650 m C) 690 m D) 620 m E) 590 m Firm} 9M4 #4. 41M: when Va=fa‘0"/,,M use. ‘51“ +0 94 X: ,_, V3: éL/oM/s = V014 a6 = 800% —-gf _ I607 'é ‘ q 8;; = lé.3sec /___ D ‘KV.,,3(+) = (eo%>(/A3m3 = 4253'" version-page: 11 14) A projectile is fired at time t = 0.05, from point 0 at the edge of a cliff, with initial velocity components of vox = 70 m/ s and voy = 500 m/ s. The projectile rises, then falls into the sea at point P. The time of flight of the projectile is 125.0 s. Vox = m/S Y P <— D —-) The y-coordinate of the projectile when its x-coordinate is 3500 m is closest to: A) --430 m m First, (3nd 414 M Mr but a +° 3dr 4° ©6750!“ X’3SOOM, #94 use «W; +9 W D) +7750 m E) 430 m f 3500M =5 a’k).€ = -—~—, f=506e¢ g= (vane + sq ea g: (sow/.Xgoua - 502.3%») (sum)a a: 95000:" -- IDDSOM = [9750”, version-page: 12 Answer Key Testname: MIDTERMI 1)C 2)C 3) B 4)C 5)D 6) C 7) E 8)C 9)C 10) A 11)E 12)B 13) B 14) B Name Student 3-digit ID version-page: 13 ...
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midterm1_wi11 grinstein - Physics 2A, Sec X00: Mechanics --...

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