MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Consider the wave shown in Figure 13-4

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1 Exam 4 Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Consider the wave shown in Figure ) Figure 13-4 The amplitude is A) 8 m. B) 2 m. C) 4 m. D) cannot be determined from given information 2) The lower the frequency of a sound wave, the 2) A) greater its wavelength. B) greater its velocity. C) lower its velocity. D) smaller its amplitude. E) shorter its period. 3) Waves on a lake pass under a floating bird causing the bird to bob up and down with a period of 3) 2.5 seconds. If the distance from wave trough to wave trough is 3.0 meters, what is the speed of the wave? A) 1.9 m/s B) 1.5 m/s C) 0.21 m/s D) 2.1 m/s E) 1.2 m/s 1

2 4) What is the frequency (in Hz) of a wave whose displacement is given y = 50. sin(0.20x + 120t), 4) where x and y are in cm and t in seconds? A) Hz B) 0.5 Hz C) khz D) 19. Hz E) 10 Hz 5) The intensity of a sound wave is proportional to its 5) A) wavelength. B) Doppler shift. C) power. D) decibel level. 6) Which of the following is a false statement? 6) A) Sound can travel through vacuum. B) Light travels very much faster than sound. C) The transverse waves on a vibrating string are different from sound waves. D) Sound waves are longitudinal pressure waves. E) "Pitch" (in music) and frequency have approximately the same meaning. TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false. 7) An object will float in a fluid if the average density of the object is greater than the density of the 7) fluid. MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 8) Which of the following is NOT a unit of pressure? 8) A) inches of mercury B) psi C) atmosphere D) N-m2 E) Pascal 9) Suppose that an 80. kg person walking on crutches supports all his weight on the two crutch tips, 9) each of which is circular with a diameter of 1.0 inch. What pressure is exerted on the floor? Express the answer in psi. A) psi B) psi C) 14. psi D) 56 psi E) psi 2

3 10) A plastic block of dimensions 2.0 cm 3.0 cm 4.0 cm has a mass of 30. grams. What is its density? 10) A) 1.3 g/cm3 B) 0.80 g/cm3 C) 2.3 g/cm3 D) 1.6 g/cm3 E) 1.2 g/cm3 11) A ship that weighs 10,000 tons (mass 10 million kg) must displace what volume of fresh water in 11) order to float? A) 107 m3 B) 1012 m3 C) 1010 m3 D) 104 m3 E) 108 m3 12) Which temperature scale never gives negative temperatures? 12) A) Celsius B) Fahrenheit C) Kelvin 13) Which of the following would correctly convert a Fahrenheit temperature (F) to a Kelvin (K) value? 13) A) K = (5/9)F B) K = (5/9)(F - 32) C) K = (5/9)F D) K = (9/5) F E) K = (9/5)(F - 32) ) Water has its density at 4. C. 14) A) maximum B) average C) minimum 15) Express your body temperature (98.6 F) in Celsius degrees. 15) A) 72.6 C B) 29.5 C C) 37.0 C D) 66.6 C E) 45.5 C 16) "Absolute Zero" is what temperature on the Celsius and Fahrenheit scales respectively? 16) A) -212 C, -273 F B) -273 C, -459 F C) -273 C, -212 F D) -459 C, -273 F E) 0 C, 459 F 17) Which two temperature changes are equivalent? 17) A) 1 C, 1 K B) 1 K, 1 F C) -40 C, -40 F D) 1 F, 1 C 3

4 18) By how much will a slab of concrete 18. m long contract when the temperature drops from 24. C to 18) -16. C? (The coefficient of linear thermal expansion for concrete is per degree C.) A) 0.86 cm B) 70. mm C) 1.5 cm D) 15. cm E) 0.5 cm 19) The coefficient of linear expansion for brass is K-1. What is its coefficient of volume 19) expansion? A) K-1 B) K-1 C) K-1 D) K-1 E) K-1 20) Which of the following is the smallest unit of heat energy? 20) A) Joule B) Btu C) calorie D) kilocalorie 21) The process whereby heat flows by means of molecular collisions is referred to as 21) A) evaporation. B) convection. C) inversion. D) conduction. E) radiation. 22) The process whereby heat flows in the absence of any medium is referred to as 22) A) conduction. B) inversion. C) radiation. D) evaporation. E) convection. 23) A 2.0 kg aluminum block is originally at 10 C. If 140 kj of heat is added to the block, what is its 23) final temperature? A) 65 C B) 78 C C) 88 C D) 45 C 24) What temperature exists inside a solar collector (effective collection area of 15 m2) on a bright 24) sunny day when the outside temperature is +20. C? Assume that the collector is thermally insulated, that the sun irradiates the collector with a power per unit area of 600 W/m2, and that the collector acts as a perfect black body. A) 93 C B) 73 C C) 154 C D) 107 C E) 33 C 4

5 25) The total energy stored in simple harmonic motion is proportional to the 25) A) amplitude. B) square of the spring constant. C) square of the amplitude. D) reciprocal of the spring constant. E) frequency of motion. 26) Doubling only the amplitude of a vibrating mass-and-spring system produces what effect on the 26) system's mechanical energy? A) increases the energy by a factor of 2 B) produces no change C) increases the energy by a factor of four D) increases the energy by a factor of three E) increases the energy by a factor of two 27) A mass is attached to a vertical spring and bobs up and down between points A and B. Where is the 27) mass located when its kinetic energy is a maximum? A) midway between A and B B) at either A or B C) one-fourth of the way between A and B 28) Doubling only the amplitude of a vibrating mass-on-a-spring system produces what effect on the 28) system frequency? A) increases the frequency by a factor of 2 B) produces no change C) increases the frequency by a factor of 4 D) increases the frequency by a factor of 3 29) Simple pendulum A swings back and forth at twice the frequency of simple pendulum B. Which 29) statement is correct? A) Amplitude of pendulum A is twice that of B. B) Amplitude can not be determined from data given. C) Amplitude of B is twice of A. D) Amplitude of A is 1.41 that of B. 5

6 30) A simple pendulum consists of a mass M attached to a weightless string of length L. For this 30) system, when undergoing small oscillations A) the frequency is independent of the length L. B) the frequency is independent of the mass M. C) the frequency is proportional to the period. D) the period is proportional to the amplitude. E) the frequency is proportional to the amplitude. 31) What happens to a simple pendulum's frequency if both its length and mass are increased? 31) A) It decreases. B) It remains constant. C) It increases. D) It could remain constant, increase, or decrease; it depends on the mass to length ratio (mass density). Consider the wave shown in Figure 13-5 below for the following item(s). Figure ) The wavelength in Figure ) A) is 4 m. B) is 8 m. C) is 2 m. D) cannot be determined from the given information. 33) The frequency in Figure ) A) is 1 Hz. B) is 2 Hz. C) is 0.5 Hz. D) is 4 Hz. E) cannot be determined from the given information. 6

7 34) What is the amplitude (in meters) of a wave whose displacement is given by 34) y = 50. sin(0.20x + 120t) cm? A) 10 m B) 1.0 m C) 6 m D) 0.50 m E) 0.20 m 35) A 2.0 kg mass is attached to the end of a horizontal spring (k = 50. N/m) and set into simple 35) harmonic motion with an amplitude of 10. cm. What is the total mechanical energy of this system? A) 1.00 J B) 0.02 J C) 0.25 J D) 25 J E) 2.5 J 36) A mass vibrates back and forth from the free end of an ideal spring (k = 20. N/m) with an 36) amplitude of 0.25 m. What is the maximum kinetic energy of this vibrating mass? A) 2.5 J B) 0.63 J C) 1.3 J D) 5.0 J E) It is impossible to give an answer since kinetic energy cannot be determined without knowing the object's mass. 37) A mass vibrates back and forth from the free end of an ideal spring (k = 20. N/m) with an 37) amplitude of 0.30 m. What is the kinetic energy of this vibrating mass when it is 0.30 m from its equilibrium position? A) 0.90 J B) zero C) 0.45 J D) 1.4 J E) It is impossible to give an answer without knowing the object's mass. 38) A mass is attached to a spring. It oscillates at a frequency of 4.0 Hz when displaced a distance of 38) 2.0 cm from equilibrium and released. What is the maximum velocity attained by the mass? A) 0.08 m/s B) 0.50 m/s C) 0.32 m/s D) 0.40 m/s E) 0.02 m/s 39) A 2-kg mass is hung from a spring (k = 18 N/m), displaced slightly from its equilibrium position, 39) and released. What is the frequency of its vibration? A) 3.0/ Hz B) 3.0 Hz C) 1.5 Hz D) 1.5 Hz E) 1.5/ Hz 7

8 40) A mass attached to the free end of an ideal spring executes SHM according to the equation 40) x = 0.5 sin(20 t) where x is in meters and t is in seconds. What is the magnitude of the maximum acceleration for this mass? A) 100 m/s2 B) (20/ ) m/s2 C) 200 m/s2 D) 10 m/s2 E) 20 m/s2 41) A mass attached to the free end of an ideal spring executes SHM according to the equation 41) x = 0.50 sin(18. t) where x is in meters and t is in seconds. What is the maximum velocity of the mass? A) 36 m/s B) 9 m/s C) 3 2 m/s D) 3 m/s E) 3 3 m/s 42) What mass should be attached to a vertical spring (k = 39.5 N/m) so that the natural vibration 42) frequency of the system will be 1.00 Hz? A) 6.29 kg B) 2.00 kg C) 1.56 kg D) 1.00 kg E) 39.5 kg 43) What is the velocity of propagation if a wave has a frequency of 12. Hz and a wavelength of 3.0 m? 43) A) 0.25 m/s B) 4.0 m/s C) 6.0 m/s D) 36 m/s E) 28 m/s 44) The equation of motion of the wave shown in Figure 13-6 is 44) Figure 13-6 A) y = 1.0 sin ( t). B) y = 0.5 cos (40t). C) y = 0.5 cos ( t). D) y = 0.5 sin (40t). E) y = 1.0 cos (2 t). 8

9 45) What is the wavelength (in meters) of a wave whose displacement is given by 45) y = 0.5 sin(0.20x + 120t), where x and y are in meters and t in seconds? A) 10. m B) 31. m C) 5.0 m D) 0.20 m E) 19. m 46) The density of water is 46) A) kg/cm3. B) kg/cm3. C) 1.0 Mg/m3. D) 1.0 kg/m3. E) g/m3. 47) When you are scuba diving, the pressure on your face plate 47) A) depends only on your depth, and not on how you are oriented. B) is independent of both depth and orientation. C) will be greatest when you are facing upward. D) will be greatest when you are facing downward. 48) "Pressure applied to an enclosed fluid is transmitted to every point in the fluid and to the enclosure 48) walls" is known as A) Kepler's law. B) Bernoulli's principle. C) Fermet's principle. D) Pascal's principle. E) Archimedes' principle. 49) Atmospheric pressure does NOT correspond to approximately 49) A) N/m2. B) lb/ft2. C) 0.1 MPa. D) oz/in2. E) 15. lb/in2. 50) The pressure differential across a wing cross section due to the difference in air flow is explained by 50) A) Archimedes Principle. B) Newton's third law. C) Bernoulli's equation. D) Poiseuille's law. E) Kepler's law. 9