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121 Phy Final Exam Fall 2010 EXAM FORM 0 This is a closed book exam. Use your own formula sheets 3 pages, 8 x 11 inches, double sided. ANY manipulation of electronic equipment (I-Pod, cell phone, laptop computer, etc.) other than your calculator is strictly prohibited, and will result in a zero on this exam. Answer all problems on the bubble scan sheet. Before you start, enter your name and student ID number on the answer sheet. Shade in the circles so that the computer can read your name and ID number. This is exam form 0. Mark 0 on the first digit of birth day on the bubble scan sheet. (Do not fill in your birth date.) You should be able to do some of the problems fairly quickly, and others will take some time and thought. Pace yourself, and dont get stuck on the hard ones. G = 6.6710-11 N m2 kg-2 Atmospheric pressure = 1.013105 Pa 273 K = 0 C R = 8.31 J/(mol K) Ice has a specific heat of 2090 J / (kg K) and a latent heat of melting of 3.33105 J / kg Liquid water has a specific heat of 4187 J / (kg K), a latent heat of vaporization of 2.26106 J / kg, and a density of 1000 kg/m3 = 1 kg/liter. Steel has a specific heat of 450 J / (kg K), thermal expansion = 1.210-5 / K, and a thermal conductivity of 14 W / (m K) u = 1.6610-27 kg NA = 6.021023 kB = 1.3810-23 J/K Speed of sound in air = 343 m/s 1. In the figure below, the 35 kg object moves to the right at 50 m/s and the 55 kg object is at rest. The objects undergo a central elastic collision (the velocities of the two objects after the collision are aligned with the incident velocity). The velocity of the incident object after the collision is (including its sign, to the right is positive) A. B. C. D. E. 11 m/s to the left 39 m/s to the left 0 m/s 39 m/s to the right 25 m/s to the left 1 Form 0 Physics 121 Final Exam 2. Which of the following statements is TRUE about sound waves? A. Sound can travel through a vacuum. B. A sound wave is a pressure wave; it can be thought of as fluctuations in pressure with respect to time. C. A sound wave is a transverse wave. D. To hear the sound of a tuning fork, the tines of the fork must move air from the fork to one's ear. E. None of the above. 3. A sphere (moment of inertia = 2 / 5 MR 2 , M=mass, R=radius) and a ring (moment of inertia= MR 2 ) with the same mass and radius are initially at rest and are then released from the top of the inclined plane shown. They roll to the bottom of the slope. What is the ratio of the velocities, vsphere / vring , at the bottom of the slope ? A. 1.2 B. 1.0 C. 0.84 D. 2.5 E. 0.40 4. If the linear density of a guitar string is increased by a factor 4, then the fundamental frequency produced by the string changes by a factor of: A. Unchanged B. 2 C . 2 D. 1/2 E. 4 5. Suppose we have 50g of ice at -10oC. We want to heat the material until it all turns to steam at 110oC. How much heat is required? A. B. C. D. E. 5.5 kcal 46 kcal 72 kcal 36.5 kcal 5000 cal 6. Driving on a highway, you enter an acceleration lane at 10 m/s. If the lane is 100 meters long, and you accelerate with uniform acceleration such that you arrive at the end of the lane with 20 m/s, when do you arrive at the end of the lane ? A. 2.3 s B. 200 s C. 6.7 s D. 1.5 s E. 3.0 s Physics 121 Final Exam 2 Form 0 7. A string is fixed at both ends and tightened until the wave speed is 50 m/s. If the frequency of the standing wave in the figure is 125 Hz what is the length of the string? A. B. C. D. E. 1.5 m 0.5 m 1.0 m 0.75 m 2.0 m 8. After bungee jumping off of the Kosciuszko Bridge, Professor Stephens notices that he is bouncing up and down, in simple harmonic motion with an amplitude of 0.5 meter and a period of 2 seconds. What is the magnitude of his velocity at the instant when he is at the equilibrium point of the oscillation? A. 1.6 m/s B. 3.4 m/s C. 0 D. 4.3 m/s E. 11 m/s 9. A block of pine wood (=0.53 g/cm3) is floating in a fluid. If only 33% of block appears above fluid what is the density of the fluid? A. B. C. D. E. 1 g/cm3 0.79 g/cm3 1.61 g/cm3 0.35 g/cm3 35 g/cm3 10. A 440.-Hz tuning fork is held above the open end of a water-filled pop bottle and resonance is heard. The length of the pop bottle (bottom to top) is 28.2 cm. If the speed of sound is 345 m/s, then to what height is the pop bottle filled with water? A. B. C. D. E. 19.6 cm 14.1 cm 11 cm 8.6 cm 20.2 cm 11. When two waves are present, A node is a point where there is always: A. B. C. D. E. a crest meeting a crest a trough meeting a through constructive interference destructive interference a double rarefaction Physics 121 Final Exam 3 Form 0 12. The block in the diagram slides with friction down the ramp. The magnitude of the work done by the frictional force is 15 J. What is the velocity of the block at the bottom of the ? incline A. 4.9 m/s B. 0.20 m/s C. 0.40 m/s D. 0.90 ms E. 6.3 m/s 13. If a horn is blaring at 1000 Hz, but it you hear it as 800 Hz, what is its velocity? You are standing still. A. 0.5 the speed of sound B. 0.75 the speed of sound toward from you C. 0.25 the speed of sound away from you D. 0.2 speed of sound away from you E. 0.8 speed of sound 14. Calculate the sound intensity 1.45 m from a 100.0 W loud speaker. Assume that the sound propagates equally in all directions. A. 4.36 W/m2 B. 47.6 W/m2 C. 54.7 W/m2 D. 3.79 W/m E. 3.79 W/m2 15. A pump uses a piston of 15 cm diameter which moves 2 cm/s. What is the fluid velocity of a tube 3 mm in diameter? A. 50 cm/s B. 6 cm/s C. 50 m/s D. 22 cm/s E. 22 m/s 16. A container has a vertical tube, whose inner radius is 24.00 mm, connected to it at its side. An unknown liquid reaches level A in the container and level B in the tubelevel A being 5.0 cm higher than level B. The liquid supports a 20.0 cm high column of oil, between levels B and C, whose density is 570 kg/m3. In the figure, the mass of the oil, in grams, is closest to: A. 410 g B. 620 g C. 820 g D. 1000 g E. 210 g Physics 121 Final Exam 4 Form 0 17. You throw a ball at an angle 60 degrees above the horizontal as hard as you can. It lands after 6 s at a distance of 60 meters away. How high does the ball rise ? (Neglect friction.) A. 15.3 m B. 30.6 m C. 6.0 m D. 24 m E. 9.8 m 18. A 8.6 kg solid sphere, made of metal whose density is 3400 kg/m3, is suspended by a cord. When the sphere is immersed in a liquid of unknown density, the tension in the cord is 38 N. The density of the liquid is closest to: A. 1700 kg/m3 B. 1600 kg/m3 C. 1500 kg/m3 D. 1900 kg/m3 E. 1400 kg/m3 19. A sealed 29 m3 tank is filled with 9000 moles of ideal oxygen gas (diatomic) at an initial temperature of 270 K. The gas is heated to a final temperature of 330 K. The atomic mass of oxygen is 16.0 g/mol. The initial pressure of the gas, in MPa, is closest to: A. 0.70 B. 0.79 C. 0.88 D. 0.61 E. 0.51 20. A planet in a circular orbit about a star of mass M is at a distance r from the star. The frequency with which the planet orbits is GM A. r2 1 GM 2 r GM C. r GM D. 2 r2 GMm E. r2 B. Physics 121 Final Exam 5 Form 0 21. A cylinder fitted with a movable piston contains ideal gas at 27C, pressure 0.50 x 105 Pa and volume 1.25 m3. What will be the final temperature if the gas is compressed to 0.80 m3 and the pressure rises to 0.82 105 Pa? A. 67.7C B. 41.8C C. 125C D. 246C E. 154C 22. A glass beaker of unknown mass contains 65.0 mL of water. The system absorbs 2000.0 cal of heat and the temperature rises 20.0C as a result. What is the mass of the beaker? (The specific heat for glass is .18 cal/(g C).) A. 560 g B. 540 g C. 270,000 g D. 190 g E. 270 g 23. This 50 kg mass is hung by a rope from the ceiling. The mass is held by the seawolf as shown. Then the seawolf releases the mass. What is the net force acting on the mass ? A. 207 N B. 444 N C. 490 N D. 103 N E. 50 N 24. The temperature is increased from 20C to 180C. By what factor does the rms speed of a molecule change? A. 1.5 B. 1.2 C. 3.0 D. 2.4 E. 6.0 25. Water flowing through a pipe suddenly comes to a section of pipe where the pipe diameter decreases to 86% of its previous value. If the speed of the water in the larger section of the pipe was 32 m/s, what is its speed in this smaller section? A. 43 m/s B. 37 m/s C. 28 m/s D. 24 m/s E. 173 m/s Physics 121 Final Exam 6 Form 0 26. A rock is thrown straight up with a speed of 15 m/s. On its path down, it falls into a well and hits the bottom 4.5 seconds after it was thrown. With which velocity hits the rock the bottom of the well ? A. 19 m/s B. 29 m/s C. 59 m/s D. 15 m/s E. 32 m/s 27. Some properties of glass are listed here. A glass window pane is 2.7 m high, 2.4 m wide and 9 mm thick. The temperature at the inner surface of the glass is 19C and at the outer surface 4C. How much heat is lost each hour through the window? A. 3.1 104 J B. 8.6 103 J C. 8.6 J D. 3.1 105 J E. 3.1 107 J 28. What is the maximum efficiency of an engine operating between a reservoir in which ice and water coexist, and a reservoir in which water and steam coexist? The pressure is constant at 1.0 atmosphere for both. A. 0.27% B. 27% C. 100% D. 1.0% E. 50% 29. Two cars approach one another at right angles at an intersection as shown. They collide and slide stuck together with 15 m/s (measured immediately after the collision). The incident velocity of the 3000 kg car is A. 35 m/s B. 28.2 m/s C. 18.6 m/s D. 30.6 m/s E. 43 m/s 30. A perfectly insulated system has work done by it at a rate of 13 W. At what rate is the internal energy of the system changing? A. 13 W B. 0 W C. -13 W D. 6.5 W E. -6.5 W Physics 121 Final Exam 7 Form 0 ... View Full Document