Phys24-001, Spring 2003 Exam 3Name _____________________________ PID: __________________ Sequence Number: 101Honor Pledge and signature: I have neither given nor received unauthorized aid on this examination. _____________________Instructions:This exam is closed book, closed notes. However, you may use a calculator.Mark your answers to the multiple-choice questions on a Scantron answer sheet.If you do not find your answer, write your solution on these pages and mark option 5.You may write on these test papers, but partial credit will not be given on the multiple-choice section.Turn in your Scantron answer sheet and these test papers at the end of the hour.Equations and conversion factors that may be useful:Acircle = r2 Vcylinder = r2h Asphere = 4r2 Vsphere = (4/3) r3  = 5.67 x 10-8 W/m2 K41. What is the buoyant force acting on a rock that is resting at the bottom of a pond?1. mg – Fn2. Fn – mg3. Fb + Fn – mg4. zero2. Blood flows through a coronary artery that is partially blocked by deposits along the artery wall. In which part of the artery is the blood pressure the greatest?1. The pressure is highest in the constricted region.2. The pressure is highest in the wide region.3. The pressure is the same throughout the artery.3. A 12-lb bowling ball has a diameter of 23 cm. Will this bowling ball float in water?1. yes2. no3. not enough information to determine4. A deflated rubber balloon is placed on a digital balance and found to have a mass of 5.0 g. It is inflated with air to a diameter of 30 cm, and placed on the same balance, which now shows a reading of 5.7 g. What is the magnitude of the buoyant force acting on this inflated round balloon?1. 0.0069 N2. 0.056 N3. 0.14 N4. 0.18 N5. A Grandfather clock is controlled by a swinging brass pendulum that is 0.90 m long and accurately keeps time at a temperature of 25 C. How much time will this clock gain or loose over the course of one day if the temperature is at 15 C?1. 8.2 s2. 9.1 s3. 16 s4. 3.5 min6. A Grandfather clock uses a swinging brass pendulum to keep time. As the room temperature rises, will the clock run fast or slow?1. fast2. slow3. neither7. Equal masses of water, sand, and iron filings are heated by identical Bunsen burners. Rank the order of the temperatures of the samples after they have each been heated 2.0 minutes under the same conditions.1. water > sand > iron2. iron > sand > water3. iron > water > sand4. water > iron > sand8. A rectangular steel plate has a hole drilled through its center. What happens to the hole as the plate is heated in a furnace?1. the diameter of the hole increases2. diameter of the hole decreases3. the diameter of the hole remains the same4. the hole becomes distorted and is no longer circular9. A cylindrical diving bell that is 2.0 m tall and 2.0 m in diameter with an open bottom is submerged to a depth of 25 m in a fresh-water lake. The surface temperature is 25 C, and the temperature 25 m down is 10 C. How high does the water rise in the bell?1. 56 cm2. 79 cm3. 121 cm4. 144 cm10. The surfaces of a Dewar flask are silvered for the purpose of minimizing heat transfer by what process?1. conduction2. radiation3. convection4. vaporization11. Estimate the efficiency of a microwave oven rated at 750 W if a cup of water (250 mL) at room temperature boils in 3.0 minutes on high.1. 40%2. 50%23. 60%4. 70%12. The surface temperature of the Sun is about 5 800 K and its radius is 6.96 x 108 m. Calculate the total energy radiated by the Sun each second. (Assume emissivity = 0.965)1. 1.1 x 1019 W2. 9.5 x 1025 W3. 3.8 x 1026 W4. 7.9 x 1030 W13. Suppose a heat engine can operate in different modes. Which mode will yield the highest efficiency?Mode A: Th = 900 K, Tc = 600 KMode B: Th = 600 K, Tc = 300 K1. Mode A2. Mode B3. both modes have the same theoretical efficiency14. According to the first law of thermodynamics, the sum of the heat gained by a system and the work done on that system is equivalent to which of the following?1. change in entropy2. change in internal energy3. change in temperature4. specific heat15. Which of the following is true for the entropy change of a system that undergoes a reversible, adiabaticprocess?1. dS < 02. dS = 03. dS > 016. One mole of an ideal gas undergoes an adiabatic expansion where it does 20 J of work on its environment. How much heat is received by the system?1. -20 J2. + 20 J3. + 5 J4. zero17. A child rides on a swing that oscillates at its natural frequency. What will happen to this natural frequency if two children ride on this swing?1. The natural frequency will increase.2. The natural frequency will decrease.3. The natural frequency will stay the same.18. Which of the following is NOT affected by increasing the amplitude of a simple harmonic oscillator?31. frequency2. maximum acceleration3. maximum speed4. total energy19. Doubling the tension in a guitar string will result in changing the fundamental frequency of the string by what factor?1. 2.02. 1.43. 0.74. 0.520. A mass of 400 g is suspended from a spring that is 45 cm long with a spring constant of 80 N/m. The mass is raised 10 cm above the equilibrium point and released from rest. What is the speed of the mass as it passes through the equilibrium point?1. 3.4 m/s2. 2.0 m/s3. 1.4 m/s4. zero4Answer Key:1 – 12 – 23 – 14 – 45 – 16 – 27 – 28 – 19 – 410 – 211 –312 – 313 – 214 – 215 – 216 – 417 – 318 – 119 – 220 –