AP Physics B 2012 Free-Response Questions

Transcription

1 AP Phyic B 01 Fee-Repone Quetion About the College Boad The College Boad i a miion-diven not-fo-pofit oganization that connect tudent to college ucce and oppotunity. Founded in 1900, the College Boad wa ceated to expand acce to highe education. Today, the membehip aociation i made up of moe than 5,900 of the wold leading educational intitution and i dedicated to pomoting excellence and equity in education. Each yea, the College Boad help moe than even million tudent pepae fo a ucceful tanition to college though pogam and evice in college eadine and college ucce including the SAT and the Advanced Placement Pogam. The oganization alo eve the education community though eeach and advocacy on behalf of tudent, educato, and chool. 01 The College Boad. College Boad, Advanced Placement Pogam, AP, AP Cental, SAT, and the acon logo ae egiteed tademak of the College Boad. Admitted Cla Evaluation Sevice and inpiing mind ae tademak owned by the College Boad. All othe poduct and evice may be tademak of thei epective owne. Viit the College Boad on the Web: Pemiion to ue copyighted College Boad mateial may be equeted online at: AP Cental i the official online home fo the AP Pogam: apcental.collegeboad.og.

2 Poton ma, Neuton ma, TABLE OF INFORMATION DEVELOPED FOR 01 CONSTANTS AND CONVERSION FACTORS m p m n kg Electon chage magnitude, e C kg electon volt, 1 ev J Electon ma, m e kg Speed of light, c m 3-1 Univeal gavitational Avogado numbe, N mol contant, G m kgi Univeal ga contant, R 8.31 J (moli K) Acceleation due to gavity at Eath uface, g 9.8 m -3 Boltzmann contant, J K k B -7 1 unified atomic ma unit, 1 u kg 931 MeV c Planck contant, h Ji evi Vacuum pemittivity, Coulomb law contant, Vacuum pemeability, Magnetic contant, -5 3 i i hc J m ev nm C Nim 0 9 k 14p Nm i C -7 m0 4p 10 (Ti m) A 7 0 i k m 4 p (T m) A atmophee peue, 1 atm N m Pa UNIT SYMBOLS mete, m mole, mol watt, W faad, F kilogam, kg hetz, Hz coulomb, C tela, T econd, newton, N volt, V degee Celiu, C ampee, A pacal, Pa ohm, W electon-volt, ev kelvin, K joule, J heny, H PREFIXES VALUES OF TRIGONOMETRIC FUNCTIONS FOR COMMON ANGLES Facto Pefix Symbol q giga G inq mega M coq kilo k tanq centi c milli m mico m nano n pico p The following convention ae ued in thi exam. I. Unle othewie tated, the fame of efeence of any poblem i aumed to be inetial. II. The diection of any electic cuent i the diection of flow of poitive chage (conventional cuent). III. Fo any iolated electic chage, the electic potential i defined a zeo at an infinite ditance fom the chage. IV. Fo mechanic and themodynamic equation, W epeent the wok done on a ytem. --

3 ADVANCED PLACEMENT PHYSICS B EQUATIONS DEVELOPED FOR 01 u u 0 + at 1 x x0 + u0t + at u NEWTONIAN MECHANICS ( x ) u0 + a x - 0 Â F F ma Ffic a c net mn u t F in q p mv J FDt Dp K 1 mu g D U mgh W FD co q P avg W Dt P Fucoq F U T -k x 1 kx p T p p T F U G 1 f G m k g Gm m - 1 Gm m - 1 a acceleation F foce f fequency h height J impule K kinetic enegy k ping contant length m ma N nomal foce P powe p momentum adiu o ditance T peiod t time U potential enegy u velocity o peed W wok done on a ytem x poition m coefficient of fiction q angle t toque 1 F kq q E F q ELECTRICITY AND MAGNETISM kq1q UE qv V Eavg - d Êq q q ˆ V ká Ë Q C V C A d 1 1 Uc QV CV DQ Iavg Dt R V A IR P IV Cp C + C + C C C1 C C3 R R + R + R R R R R p FB 1 3 qub inq F BI inq B m0 I B p fm BA co q Df eavg - Dt e B u m A aea B magnetic field C capacitance d ditance E electic field e emf F foce I cuent length P powe Q chage q point chage R eitance ditance t time U potential (toed) enegy V electic potential o potential diffeence u velocity o peed eitivity q angle f magnetic flux m -3-

4 ADVANCED PLACEMENT PHYSICS B EQUATIONS DEVELOPED FOR 01 FLUID MECHANICS AND THERMAL PHYSICS mv P P + gh Fbuoy Au 0 Vg A u P + gy + u D a H P 0 DT kadt L F A PV nrt NkBT K u W avg m 3 kbt cont. 3k T m 3RT B M - PDV D U Q + W e e c W Q T H H - T H T C ATOMIC AND NUCLEAR PHYSICS E hf pc Kmax hf - f l h p DE ( Dmc ) A aea e efficiency F foce h depth H ate of heat tanfe k themal conductivity K avg aveage molecula kinetic enegy length L thickne m ma M mola ma n numbe of mole N numbe of molecule P peue Q heat tanfeed to a ytem T tempeatue U intenal enegy V volume u velocity o peed u m oot-mean-quae velocity W wok done on a ytem y height a coefficient of linea expanion m ma of molecule denity E enegy f fequency K kinetic enegy m ma p momentum l wavelength f wok function WAVES AND OPTICS u f l n n c u in q n n n in q 1 1 inq c i 0 f h i M - i h f din R 0 0 q ml l x ª m L m d d epaation f fequency o focal length h height L ditance M magnification m an intege n index of efaction R adiu of cuvatue ditance u peed x poition l wavelength q angle GEOMETRY AND TRIGONOMETRY Rectangle A bh Tiangle 1 A bh Cicle A p C p Rectangula Solid V wh Cylinde V p S p + p Sphee 4 3 V p 3 S 4p Right Tiangle a + b c a inq c b coq c a tanq b A aea C cicumfeence V volume S uface aea b bae h height length w width adiu q c b 90 a -4-

5 01 AP PHYSICS B FREE-RESPONSE QUESTIONS PHYSICS B SECTION II Time 90 minute 7 Quetion Diection: Anwe all even quetion, which ae weighted accoding to the point indicated. The uggeted time ae about 11 minute fo anweing each of Quetion, 3, 4, 6, and 7 and about 17 minute fo anweing each of Quetion 1 and 5. The pat within a quetion may not have equal weight. Show all you wok in thi booklet in the pace povided afte each pat. 1. (15 point) Block A of ma.0 kg i pulled along a hoizontal table by a foce of 15 N, which i applied by a light ting that pae ove a light fictionle pulley, a hown above. The coefficient of kinetic fiction between the block and the uface i 0.5. (a) On the dot below, which epeent the block, daw and label the foce (not component) that act on the block a it i pulled aco the table. (b) Calculate the magnitude of the acceleation of the block. 01 The College Boad. -5-

6 01 AP PHYSICS B FREE-RESPONSE QUESTIONS The applied foce i emoved. Block B of ma 1.5 kg i now attached to the ting, a hown above. The ytem i eleaed fom et o that the 1.5 kg box decend and the.0 kg block i again pulled aco the table. (c) Calculate the acceleation of the 1.5 kg block a it decend. (d) Calculate the tenion in the ting connecting the two block. (e) Calculate the ditance that the 1.5 kg block decend in (f) If thi ytem i et up in a laboatoy and the acceleation of the 1.5 kg block i expeimentally detemined, the expeimental value i found to be malle than the value calculated above. If the given value fo the coefficient of fiction i coect and ai eitance i negligible, explain biefly, but pecifically, why the expeimental value of the acceleation i malle. 01 The College Boad. -6-

7 01 AP PHYSICS B FREE-RESPONSE QUESTIONS. (10 point) A mall and a lage phee, of ma M and 3M epectively, ae aanged a hown on the left ide of the figue above. The phee ae then imultaneouly dopped fom et. When the lage phee tike the floo, the phee have fallen a height H. Aume ai eitance i negligible. Expe all anwe in tem of M, H, and fundamental contant, a appopiate. (a) Deive an expeion fo the peed u b with which the lage phee tike the floo. Immediately afte tiking the floo, the lage phee i moving upwad with peed u b and collide head-on with the mall phee, which i moving downwad with identical peed u b at that intant. Immediately afte the colliion, the mall phee move upwad with peed u S and the lage phee ha peed u L. (b) Deive an equation that elate u b, u S, and u L. In thi paticula ituation u L 0. (c) Ue you elationhip fom pat (b) to detemine the peed of the mall phee in tem of u b. (d) Indicate whethe the colliion i elatic. Jutify you anwe uing you eult fom pat (b) and (c). (e) Detemine the height h that the mall phee ie above it lowet poition, in tem of the oiginal height H. 01 The College Boad. -7-

8 01 AP PHYSICS B FREE-RESPONSE QUESTIONS 3. (10 point) A gla U-tube with a unifom diamete of cm i ued to detemine the denity of an oil. A hown in the figue above, a 4.5 cm column of wate balance a 7. cm column of the oil o that inteface A and B of the 3 3 mecuy with the othe liquid ae at the ame height. The denity of wate i kg m. (a) Calculate the denity of the oil. (b) Calculate the abolute peue at B, the inteface between the wate and the mecuy. A new tube, identical to the U-tube except fo a cone hape on the left, a hown above, i filled with the ame volume of mecuy that wa in the U-tube. The mecuy i at the ame height on both ide of the new tube a it wa in the U-tube, a hown by the dahed line. The ame volume of oil and wate that wee in the U-tube ae now poued into the new tube, on the left and ight epectively. (c) Indicate the new poition of B elative to A. Above A Below A At the ame height a A Jutify you anwe. (d) A mall piece of wood with denity le than that of the oil i placed o that it float in the left ide of the tube. Indicate whethe the peue at the bottom of the tube inceae, deceae, o emain the ame. Inceae Deceae Remain the ame 01 The College Boad. -8-

9 01 AP PHYSICS B FREE-RESPONSE QUESTIONS 4. (10 point) A cylindical containe i fitted with a fictionle piton that i initially locked in place. The cylinde contain a fixed amount of an ideal ga that i initially at oom tempeatue and atmopheic peue. (a) The cylinde i placed in a hot-wate bath. On the axe below, ketch a gaph of peue veu tempeatue fo the poce the ga undegoe a a eult, and indicate the diection of the poce on the gaph. (b) The cylinde i emoved fom the hot-wate bath. Afte equilibium i eached, the lock i emoved o the piton i fee to move. Indicate whethe the piton move up, move down, o emain tationay. Move up Move down Remain tationay Jutify you anwe. (c) When the ytem i again at equilibium, the piton i puhed down vey lowly. On the axe below, ketch a gaph of peue veu volume fo the poce the ga undegoe a a eult, and indicate the diection of the poce on the gaph. Label thi poce C. (d) Now the piton i pulled up quickly, o no heat i added to o emoved fom the ga duing the poce. On the axe above, ketch a gaph of peue veu volume fo the poce the ga undegoe a a eult, and indicate the diection of the poce on the gaph. Label thi poce D. 01 The College Boad. -9-

10 01 AP PHYSICS B FREE-RESPONSE QUESTIONS 5. (15 point) Fou lightbulb ae connected in a cicuit with a 4 V battey a hown above. (a) i. Detemine the aveage potential enegy change of an electon a it move fom point Z to point X. ii. Indicate whethe the electon gain o loe potential enegy a it move fom point Z to point X. Gain enegy Loe enegy (b) Calculate the equivalent eitance of the cicuit. (c) i. Calculate the magnitude of the cuent though point Y. ii. Indicate on the diagam the diection of the cuent though point Y. (d) Calculate the enegy diipated in the 1 W bulb in 5. (e) Rank the bulb in ode of bightne, with 1 being the bightet. If any bulb have the ame bightne, give them the ame anking. Bulb A Bulb B Bulb C Bulb D 01 The College Boad. -10-

11 01 AP PHYSICS B FREE-RESPONSE QUESTIONS 6. (10 point) You ae given the appaatu epeented in the figue above. A gla tube i fitted with a movable piton that allow the indicated length L to be adjuted. A ine-wave geneato with an adjutable fequency i connected to a peake nea the open end of the tube. The output of a micophone at the open end i connected to a wavefom diplay. You ae to ue thi appaatu to meaue the peed of ound in ai. (a) Decibe a pocedue uing the appaatu that would allow you to detemine the peed of ound in ai. Clealy indicate what quantitie you would meaue and with what intument each meauement would be made. Repeent each meaued quantity with a diffeent ymbol. (b) Uing the ymbol defined in pat (a), indicate how you meauement can be ued to detemine an expeimental value of the peed of ound. (c) A moe accuate expeimental value can be obtained by vaying one of the meaued quantitie to obtain multiple et of data. Indicate one quantity that can be vaied, and decibe how a gaph of the eulting data could be ued to detemine the peed of ound. Clealy identify independent and dependent vaiable, and indicate how the lope of the gaph elate to the peed of ound. 01 The College Boad. -11-

12 01 AP PHYSICS B FREE-RESPONSE QUESTIONS 7. (10 point) The momentum of a paticula poton i quetion kgi m. Relativitic effect can be ignoed thoughout thi (a) Calculate the de Boglie wavelength of the poton. (b) Calculate the kinetic enegy of the poton. The poton i diected towad a vey ditant tationay uanium nucleu, 35 9 U. The poton eache a ditance D fom the cente of the nucleu and then evee diection. Aume that the nucleu i heavy enough to emain tationay duing the inteaction. (c) Calculate the value of D. (d) Afte the poton ha moved away, the 35 9 U nucleu pontaneouly fiion into La and 35B, along -11 with thee neuton. A a eult,.5 10 J of enegy i eleaed. Indicate whethe the ma of the 35 nucleu i geate o le than the ma of the fiion poduct. Geate Le Calculate the ma diffeence. 9 U STOP END OF EXAM 01 The College Boad. -1-