DO NOT OPEN THIS EXAM BOOKLET UNTIL INSTRUCTED TO DO SO.

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1 PHYSICS 1 Fll 017 EXAM 1: October 3rd, 017 8:15pm 10:15pm Nme (printed): Recittion Instructor: Section #: DO NOT OPEN THIS EXAM BOOKLET UNTIL INSTRUCTED TO DO SO. This exm contins 5 multiple-choice questions, plus extr-credit questions, ech worth 3 points. Choose one nswer only for ech question. Choose the best nswer to ech question. Answer ll questions. Allowed mteril: Pencils, ersers, rulers nd your clcultor. Eerything else, including bgs, cots, hts/cps etc., must be left in the front of the room. Hedphones or erbuds re not llowed. There is formul sheet ttched to the exm. Other copies of the formul sheet re not llowed. Clcultor: In generl, ny clcultor, including clcultors tht perform grphing, is permitted. Electronic deices tht cn store lrge mounts of text, dt or equtions (like lptops, tblets, or phones) re NOT permitted. If you re unsure whether or not your clcultor is llowed for the exm, sk your instructor. No cell phones nd no smrtwtches llowed. Turn them off nd lee them in your bg. Anyone using cell phone or smrtwtch in ny mnner must hnd in their work immeditely; their exm is oer. How to fill in the bubble sheet: Use number pencil. Do NOT use ink. If you did not bring pencil, sk for one. Write nd fill in the bubbles corresponding to: o Your lst nme, middle initil nd first nme. o Your ID number (the middle 9 digits on your ISU crd) o Specil codes K to L re your recittion section. Use two digits: 01, 0, etc. Honors section: enter 34. Turn oer or hide your bubble sheet when you re not writing on it. If you need to chnge ny entry, you must completely erse your preious entry. Right before you turn in your exm (nd not before tht!), you must enter your exm ersion (to be found inside this booklet) in the KEY spce of the bubble sheet. All clcultions re to be done on this exm booklet. If you need extr pper, request it from the instructors, nd mke sure tht you turn tht in with the rest of the exm. When you re finished with the exm: Mke sure tht your nswers on your bubble sheet re wht you intend them to be. Mke sure tht you circle your nswers in this exm booklet. You my lso copy down your nswers on piece of pper to tke with you nd compre with the posted nswers. You my use the tble t the end of the exm for this. The only pper you re llowed to tke with you is this tble with your nswers. Nothing else should be written on this nswer pper. All exm mterils except your nswer tble re to be turned in. Stple eerything (booklet, formul sheet, dditionl pper) except the bubble sheet, nd hnd them to your instructor. Best of luck, Drs. Cnfield nd Herrer 1

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3 This is ersion A of the exm. At the end of the exm, right before you turn in your exm, enter the ersion in your bubble sheet in the KEY spce. DO NOT DO THIS UNTIL YOU ARE READY TO TURN IN YOUR EXAM 3

4 Note: For ll problems in this exm, ssume tht ir resistnce is negligible unless stted otherwise. 1. Let A 3iˆ 0ˆj 4kˆ nd B 5iˆ 4ˆj 0kˆ. Wht is the mgnitude of the projection of B onto the direction of A? A. 1.0 B..1 C. 3.0 D. 6.4 E. 15. A crt moes long the x xis. Its elocity s function of time is shown below. At time t = t 1: A. The ccelertion is t its mximum lue (within the shown interl). B. The ccelertion is zero. C. The crt reerses its direction of motion. D. The crt is t the sme position s t t = 0. E. The crt is the furthest from its initil position (within the shown interl). x t = 0 t 1 t 4

5 3. An object moes long the x xis. Its position s function of time is: x t m m 3 s t s t Wht is the position of this object when it reerses its direction of motion? A. 0.4 m B m C m D m E. 1.0 m 4. An old inyl LP record with dimeter 30 cm rottes t 33.3 reolutions per minute on turntble. Its owner then turns off the turntble, nd the record slows down t constnt rte until it comes to stop fter exctly 4.0 complete reolutions. Wht is the mgnitude of the ngulr ccelertion of the record during this process? A. 0.4 rd/s B rd/s C. 1. rd/s D.. rd/s E. 140 rd/s 5

6 5. The only two forces cting on certin object re in the plne of this pper. Their directions nd mgnitudes re shown below. Find the mgnitude of the net force on the object. A. 7.1 N B. 15 N C. 36 N D. 50 N E. 70 N y = 60 F 1 = 30 N x F = 40 N 6. A 6.00-kg mss is hung from wire mounted on the roof s shown. The length of the wire is 14.0 m (i.e., on ech side of the mss there is L = 7.00 m of wire) nd the erticl distnce to the roof is h = 1.00 m. Wht is the tension in the wire? A N B. 9.8 N C. 103 N D. 178 N E. 06 N L h L 6

7 7. A child throws snowbll from tree house tht is in the middle of flt bckyrd. The snowbll lees the child s hnd when it s 4.0 m off the ground, nd lnds on the ground 1. s lter, fter treling 10 m in the horizontl direction. At wht ngle boe the horizontl ws the bll thrown? A. 11 B. 17 C. 3 D. 6 E Two smll reflectors 1 nd re plced t two different loctions on bicycle wheel tht rottes t r1 constnt ngulr speed. The rtio between their distnces to the center is k. Find the rtios r between i) the liner speeds nd ii) the mgnitude of the ccelertions of the reflectors. A B. k 1 C. 1 D. E. 1 1 k 1 1 k 1 1 k k k k 1 7

8 9. Jonh nd Lucs bike on cmpus ner Lke LVerne. They both ride t bout 5 mph. Which of the ectors below best describes the elocity of Lucs reltie to Jonh? C B Lucs A D Jonh E Lke LVerne 10. Two blocks of msses 1.5 kg nd 3.0 kg re on horizontl nd frictionless surfce. They re pushed by force F = 150 N tht mkes n ngle = 30 with the horizontl, s shown in the figure. Find the mgnitude of the force between the blocks. A. 15 N B. N C. 30 N D. 43 N E. 50 N = 30 F = 150 N 3.0 kg 1.5 kg 8

9 11. A lmp hngs on cble from the ceiling of n eletor. Consider the following scenrios: 1. The eletor is t rest nd its ccelertion is zero.. The eletor is moing upwrd t constnt elocity. 3. The eletor hs constnt ccelertion upwrds. Rnk the tension in the cble between the lmp nd the ceiling in ech scenrio. A. T 1 = T = T 3 B. T 1 = T > T 3 C. T 1 = T < T 3 D. T 1 > T = T 3 E. T 1 < T = T 3 1. In the system below, the coefficient of kinetic friction between block A nd the tble is The mss of block A is 15.0 kg. Assume the pulley nd the string re idel. The system is obsered to moe t constnt elocity. Wht is the mss of block B? A..5 kg B kg C kg D kg E..0 kg 9

10 13. The force on body of mss m locted t distnce r from some origin hs mgnitude m F A r 4, where A is constnt. Wht re the units of A in the SI system? A. B. C. D. E. N m kg N m kg s 4 kg m s 5 kg m s 5 m s Which of the following is TRUE sttement? A. Norml forces re lwys perpendiculr to the motion. B. The mgnitude of the norml force is lwys equl to mg. C. The norml force lwys cncels out the weight of n object. D. The norml force is Newton s 3 rd lw pir to the weight of n object. E. The norml force is lwys perpendiculr to the contct surfce. 10

11 15. In the figures below, mss or msses moe with constnt speed 0. The pulleys nd the ropes cn be considered s mssless, nd the pulleys he no friction t their xis. Compre the tension in the rope supporting the pulley for the two cses. A. T 1 > T lwys B. T 1 < T lwys C. T 1 = T only if 0 = 0 D. T 1 = T for ny constnt speed E. This cnnot be nswered without knowing the mgnitude of the force exerted by the person in figure A block with mss M is ttched to wll by rope nd is t rest on n incline, s shown in the figure below. Assume tht the rope is mssless. If M = 8.0 kg nd = 37.0, wht is the tension in the rope? A. 75 N B. 165 N C. 19 N D. 195 N E. 134 N 11

12 17. In conicl pendulum, mss m is ttched to fixed point on the roof by rope of length L, nd moes in circles t constnt speed in such wy tht the string mkes n ngle with the erticl, s shown below. If the tension in the rope is T, wht is the speed of the mss? A. TLsin m B. TLsin T sin C. m TLsin D. m Lsin E. m m L θ 18. A block moes cross the floor with constnt elocity. The coefficient of friction between the block nd the floor is K. Which of the following is then necessrily TRUE? A. There is no force, of ny sort, on the block. B. The only force on the block is the force of friction. C. The force of friction must be equl in size nd opposite in direction to the norml force. D. There must be some force (or sum of forces) tht is equl in size nd opposite in direction to the frictionl force. E. The force of friction must be ery smll, close to zero. 1

13 19. Terminl elocity A. occurs only just before deth. B. occurs when the fluid resistnce is equl to n object s weight. C. occurs when there is still finite net force on the flling object. D. only occurs when there is finite rdil ccelertion. E. does not depend on the flling object s shpe. 0. A truck with box plced on its fltbed ccelertes fter the stoplight turns green. The box does not slip with respect to the truck s fltbed surfce. Which of the ectors shown below best describes the frictionl force on the box s the truck is ccelerting? A. Vector A B. Vector B C. Vector C D. Vector D E. There is no frictionl force. 1. Which of the following re consertie forces? 1) Grittionl force ) Force from spring 3) Frictionl force A. Only 1 is consertie B. Only is consertie C. Only 3 is consertie D. 1 nd re consertie E. nd 3 re consertie 13

14 . The coefficient of kinetic friction between 1.0 kg block nd the floor is K = A force of mgnitude F = 6.0 N is pplied on the block s shown in the figure. Wht is the work done by F s the block slides cross 15.0 m of floor? A. 15 J B. 390 J C. 338 J D. 195 J E. 65 J N F x 3.00 x m. Wht work does this force do on the mss s it moes from x = 3.00 m to x = 4.00 m? 3. A force tht cts on mss M =.00 kg hs the form A J B J C. 1.0 J D J E. 1.4 J 14

15 4. A bll of mss m =.00 kg is dropped, from rest, from height of 5.0 m boe the ground. There is no ir resistnce. Which of the following plots of mechnicl energy ersus distnce from the ground, y, best represents the bll s totl mechnicl energy s it drops? A B C D E 5. A mss slides long frictionless loop-the-loop. Two experiments re conducted. First, the mss strts from rest t point A. The second time, it strts from rest t point B. Point C is the highest point of the loop-the-loop. Which of the following sttements is/re TRUE? 1) The potentil energy of the mss t point C is lrger when it strts t A. ) The norml force between the trck nd the mss t point C is lrger when it strts t A. 3) The weight of the mss t point C is lrger when it strts t A. 4) The kinetic energy of the mss t point C is lrger when it strts t A. A. Only 1 is true B. Only nd 3 re true C. Only 4 is true D. Only nd 4 re true E. Only 1, nd 4 re true 15

16 J U x 5.00 x m 4 be the potentil energy of n object tht cn moe long the x xis. Wht is the x component of the force on the object when its position is x = 3.00 m? 6. Let 4 A N B N C N D. 405 N E. 540 N 7. In the system below, both the string connecting the blocks nd the pulley cn be considered mssless. The pulley cn rotte freely bout its xis. The blocks he msses m 1 = 10.0 kg nd m = 5.00 kg. Wht is the mgnitude of the ccelertion of m 1 if the system is free to moe? A. 3.7 m/s B m/s C m/s D m/s E. 9.4 m/s 16

17 BEFORE YOU TURN IN THE EXAM, MAKE SURE YOU HAVE BUBBLED IN YOUR EXAM VERSION IN THE KEY SPACE OF YOUR SCANTRON. You my record your nswers on this pge nd tke it with you fter the exm to compre to the solutions tht will be posted online. VERSION Do not write on this pge except to record your results in the tble boe 17

18 DO NOT WRITE ON THIS PAGE 18