PHYS 2425 - Brooks The Final Exam is comprehensive and will cover chapters 1-21. To review chapters 1-11, refer to the prior reviews for these chapters. This review only covers material from chapters 12-21. The Final Exam will include 1 or 2 problems from each chapter (1-21). This practice test is similar to the actual test. The Final Exam will consist of about 30 questions designed to be completed in about 2 hours. This practice test does not cover every single concept that may be on the actual Final Exam. An answer key is included, but there are no solutions to the problems. Students need to work out all solutions on their own.

Select the response that best answers the given statement.

1. An object in equilibrium always:

a. is not moving

b. is not accelerating

c. has no forces acting upon it

d. has all forces acting upon it of equal magnitude.

2. If the net force on an object is zero, then the object must be at rest.

a. true

b. false

c. cannot say unless gravity is negligible

3. Materials which behave as described by Hooke's law have a constant

elastic force.

a. true

b. false

c. only until the proportionality limit is reached

4. What is the stress in a 1.33 meter long, 1.0 mm diameter, brass wire

which has been stretched 1.5 mm? Young's modulus for brass is

1.00 x 1011 N/m2

a. 89. N/m2

b. 8.9 x 105 N/m2

c. 1.1 x 1011 N/m2

d. 1.1 x 108 N/m2

5. For a horizontal beam spanning an opening, the shear stress is greatest

at:

a. the center

b. one third the distance from each end

c. the end

d. one quarter the distance from each end

Name:

Section:

6. For a concrete column of constant cross sectional area, what is the

maximum possible height if the compressible strength is 2.0 x 107 N/m2?

The density of concrete is 2.3 x 103 kg/m3. a. 0.47 km

b. 0.89 km

c. 89 m

d. 47 m

7. A 1.0 cm diameter cable is continuously lowered into the ocean supporting

its own weight. At a depth of 1.5 km it breaks. A new replacement cable

made of the same glass fiber only with twice the diameter (2.0 cm) would

be expected to break at what depth?

a. 1.5 km

b. 3.0 km

c. 4.5 km

d. 6.0 km

8. What is the minimum cross sectional area required for an aluminum cable

to support a 100 kg person hanging from the cable end? Assume a safety

factor of 4. The tensile strength of aluminum is 2.00 x 108 N/m2.

a. 0.15 cm2

b. 0.20 cm2

c. 0.33 cm2

d. 0.72 cm2

9. Jason and Jane stand on opposite ends of a balanced seesaw. How far (x)

is Jason from the fulcrum when Jane is 3.0 from the fulcrum?

a. 2.1 m

b. 1.8 m

c. 4.2 m

d. 3.9 m

10. What minimum mass counterweight (C) must be used in the tower crane to

enable it to lift 4600. kg?

a. 3.2 Mg

b. 4.6 Mg

c. 5.9 Mg

d. 6.5 Mg

11. An aluminum rivet must withstand a shear force of 2000. N. Using a safety

factor of 5, what area rivet must be used?

a. 0.50 cm2

b. 1.0 cm2

c. 2.0 cm2

d. 2.5 cm2

12. A 1.9 m long flagpole of uniform 0.75 kg mass is attached to the wall by

a bracket making a 40 degree angle with the wall. The bracket must exert

what torque to support the pole?

a. 4.5 N-m

b. 5.3 N-m

c. 0.46 N-m

d. 0.49 N-m

13. At a point in a fluid

a. pressure downward is greater than pressure sideways because of gravity

b. pressure downward is greater than pressure upward

c. pressure is the same in all directions only if the fluid is at rest

d. pressure downward equals pressure sideways

14. A dam is 32 m high and 1200 m wide. Calculate the total horizontal force

exerted on the dam by the water on the dam.

a. 6.0 x 109 N

b. 9.9 x 109 N

c. 1.4 x 1010 N

d. 1.8 x 1010 N

15. One atmosphere is equal to:

a. 1 bar

b. 1.000 x 105 N/m2

c. 1.013 x 105 N/m2 d. 1 Pascal

16. A water barometer is about how high?

a. 76 cm

b. 14.7 inches

c. 760 ft

d. 10 m

17. Consider ice cubes floating in a full glass of water. When they melt:

a. water overflows the edge

b. the water level drops

c. the water level remains the same

18. A 1.0 cm3 sphere of copper (specific gravity 8.9) is lowered by string

into a bucket of gasoline (0.68 specific gravity). It seems to weigh how

much less?

a. 6.7 x 10-3 N

b. 8.9 x 10-3 N

c. 6.8 x 10-4 N

d. 2.2 x 10-3 N

19. A 2.5 cm diameter sphere just barely floats in water. What is its weight?

a. 1.0 mN

b. 4.1 mN

c. 8.2 mN

d. 24 mN

20. An incompressible fluid flows through a cylindrical pipe. When the radius

doubles, the velocity of flow:

a. doubles

b. triples

c. quadruples

d. stays the same

21. Water is pumped throughout a neighborhood. It moves 1.3 m/s through a 5.5

cm diameter pipe under 4.0 atm pressure at the bottom of a hill. What is

its speed when it reaches the top of the 9.0 m hill where the pipe

narrows to 4.2 cm diameter? Viscosity can be neglected.

a. 2.2 m/s

b. 1.7 m/s

c. 0.99 m/s

d. 0.76 m/s

22. A 20. N force is applied to the input 1.7 cm diameter piston of a

hydraulic lift. What lifting force is produced at the output?

a. 1.4 KN

b. 1.6 x 102 N c. 82. N

d. 20. N

23. If A is the amplitude of a vibrating mass on a spring, then the mass in

one period travels a distance:

a. 0

b. A

c. 2 A

d. 4 A

24. In Simple Harmonic Motion, the velocity is greatest at:

a. maximum acceleration

b. minimum acceleration

c. maximum displacement

d. maximum stored energy

25. A simple harmonic oscillator has an amplitude of 5.0 cm, a spring

constant 5.0 N/m, and a maximum speed of 10. m/s. What is the speed when

it reaches half of the amplitude?

a. 8.7 m/s

b. 5.0 m/s

c. 7.6 m/s

d. 2.5 m/s

26. A 300 gram mass is oscillating on a spring (spring constant 30 N/m). The

damping force is proportional to velocity (Fd = -bv). This friction

reduces the oscillation frequency to 1.4 Hz. What is the damping constant

b?

a. 2.9 N-s/m

b. 4.3 N-s/m

c. 6.7 N-s/m

d. 8.1 N-s/m

27. What length simple pendulum produces a "seconds" clock (i.e. the half

period is 1.00 second)?

a. 24.8 cm

b. 42.8 cm

c. 93.9 cm

d. 99.3 cm

28. Peter notices a lamp hung by a light chain to the ceiling. Peter counts

85.0 cycles in 592 seconds. How high is the ceiling above the lamp?

a. 12.0 m

b. 13.0 m

c. 14.0 m

d. 15.0 m

29. A wave traveling 12 m/s has a frequency of 3.0 Hz. How far is it from a

crest to an adjacent trough?

a. 1.0 m

b. 2.0 m

c. 3.0 m

d. 4.0 m

30. The tension in a stretched rubber cord, of mass 12.0 grams and length 2.0

meters, is 54 mN. What is the speed of a transverse wave?

a. 2.1 m/s

b. 3.0 m/s

c. 4.5 m/s

d. 9.0 m/s

31. Given that iron rails have an elastic modulus of 100 x 109 N/m2 and density 7.9 grams/cc, what is the speed of sound in the rails?

a. 1.1 x 105 m/s b. 3.2 km/s

c. 3.6 km/s

d. 4.2 km/s

32. If the intensity of light reaching the earth from the sun is

approximately 1 kW/m2, what is the intensity leaving the solar surface?

(sun diameter = 14 x 108 m, earth diameter = 12.7 x 106 m, earth-sun

distance = 1.5 x 1011 m)

a. 2.1 x 102 kW/m2

b. 4.6 x 104 W/m2

c. 2.1 x 105 W/m2

d. 4.6 x 107 W/m2

33. Consider a transverse wave represented by the function

y = 2.3 sin (1.9x - 25. t) where y, x, and t are in meters, meters, and

seconds respectively. Determine the period in seconds.

a. 3.3

b. 0.25

c. 2.3

d. 13.

e. 4.0

34. Consider a transverse wave represented by the function y = 2.3 sin (1.9x

- 25. t) where y, x, and t are in meters, meters, and seconds

respectively. Determine the speed in m/s.

a. 3.3

b. 0.25

c. 2.3

d. 13.

e. 4.0

35. Consider a transverse wave represented by the function y = 2.3 sin (1.9x

- 25. t) where y, x, and t are in meters, meters, and seconds

respectively. What is the displacement in meters at x = 4.0 m at t = 200

ms?

a. 0.10

b. 0.52

c. 0.92

d. 1.2

36. A string fixed at both ends vibrates in its 3rd overtone with a distance

between nodes of 30 cm. How long is the string?

a. 7.7 cm

b. 10 cm

c. 90 cm

d. 1.2 m

37. The 1st overtone of a violin string is 576 Hz. Which of the following is

not a possible harmonic?

a. 1.15 KHz

b. 1.34 KHz

c. 288. Hz

d. 864. Hz

38. The result of "interfering" waves is always smaller than the original

waves.

a. True

b. False

39. What is the ratio of the speed of sound in air at freezing temperature

(0° C) to the speed at room temperature (20° C)? a. 0.965

b. 1.04

c. 0.0363

d. 27.6

40. The intensity of sound is often expressed in:

a. watts

b. decibels

c. Pascals

d. Newtons

41. Frequencies of sound higher than 20 Khz are called:

a. supersonic

b. infrasonic

c. transonic

d. ultrasonic

42. An 80 dB sound has which of the following intensities?

a. 10-4 W/cm2

b. 10-6 W/cm2

c. 10-8 W/cm2

d. 10-10 W/cm2

43. How many dB is an intensity of 10-5 W/m2?

a. 50

b. 70

c. 5

d. 7

44. Which of the following is not a vibration mode for a tube closed at one

end?

a. 1st overtone

b. 1st harmonic

c. 3rd harmonic

d. 43rd harmonic

45. Consider a closed 30.0 cm long organ pipe. What is the frequency of the

2nd overtone when the sound speed is 336 m/s?

a. 0.560 Khz

b. 0.840 Khz

c. 1.12 Khz

d. 1.68 Khz

46. There is constructive interference of two coherent sound waves when the

path difference is how many wavelengths?

a. an integer

b. any half integer

c. half an odd integer

d. an even integer plus one half

47. One has destructive interference of two coherent sound waves when the

path difference is how many wavelengths?

a. an odd integer

b. an even integer

c. half an even integer

d. half an odd integer

48. Assume ultrasound waves travel through the body of an animal at 1540 m/s.

If a 30,000 Hz signal were reflected off a portion of a heart which was

moving toward the observer at 4 m/s, what frequency signal would return

to the stationary observer?

a. 30000. Hz

b. 29920. Hz

c. 30072. Hz

d. 30078. Hz

49. Beats are produced when two sound waves have:

a. the same frequency

b. the same intensity

c. slightly different frequencies

d. slightly different intensities

50. Suppose a boat moving at 6.0 m/s creates a bow wave at an angle of 42° with the line of track. What is the speed of the surface water waves?

(From section 16-8. This concept will not be on the Final Exam.)

a. 3.0 m/s

b. 4.0 m/s

c. 5.0 m/s

d. 9.0 m/s

51. A certain material has 2.8 x 1028 atoms/m3. Estimate the distance between neighboring atoms:

a. 0.10 nm

b. 0.13 nm

c. 0.23 nm

d. 0.33 nm

52. At 376° C and 1.00 atm pressure, a certain gas occupies 7.25 m3. If the temperature decreases to 186° C with the pressure remaining constant, what is the final volume?

a. 5.13 m3

b. 10.3 m3

c. 3.59 m3

d. 14.7 m3

53. How many molecules are contained in a gas at 3.5 atm, 194° F, and

occupying 33 m3?

a. 2.3 x 1027

b. 1.2 x 1027

c. 4.4 x 1027

d. 0.77 x 1027

54. Which of the following is not an assumption of the basic kinetic theory?

a. the number of molecules is large

b. molecules obey Newton's laws

c. molecules lose energy hitting the walls and thereby exert pressure

d. molecules spend a high percentage of their time separated from

neighbors

55. The pressure of the gas depends upon

a. average speed squared

b. average squared speed

c. square of the average speed

d. root-mean-square speed

56. What is the average translational kinetic energy of molecules at 5500 K

(the approximate temperature of the sun's surface)?

a. 1.1 x 10-19 eV b. 0.025 eV

c. 0.41 eV

d. 0.71 eV

57. Estimate the rms speed of hydrogen atoms (1.67 x 10-27 kg each) at 5500 K.

a. 1.4 x 108 m/s

b. 6.3 x 105 m/s c. 9.0 km/s

d. 12 km/s

58. Which of the following is not a unit of heat?

a. Joule

b. calorie

c. watt

d. N-m

59. The mechanical equivalent of heat says

a. 1 cal = 4.186 J

b. 1 cal = 1 J

c. 1 J = 4.186 cal

d. 1 kcal = 1 J

60. Temperature is a measure of the average:

a. total energy of individual molecules

b. kinetic energy of individual molecules

c. total energy of all molecules in a sample

d. total kinetic energy of all the molecules

61. The specific heat of liquid water is unusual in that it is:

a. much greater than most metals

b. about equal to that of most metals

c. much less than most metals

d. much less than frozen water

62. Four moles of Helium at 15° C are isothermally expanded from 72 liters to 233 liters. How much work did the gas do?

a. +11.2 KJ

b. -11.2 KJ

c. 586. J

d. -586. J

63. When the absolute temperature of an object triples, its radiation emitted

is how many times more?

a. 3

b. 27

c. 81

d. 243

64. Estimate the power radiated from a human body approximating it to be a

black body at 37° C with a surface area of 1.5 square meters surrounded by walls at 20° C

a. 0.11 Kw

b. 0.16 Kw

c. 7.1 Kw

d. 0.79 Kw

65. The emissivity of most stars is close to one so they can be treated as

"black bodies". Consider two stars, the second having twice the surface

temperature and five times the radius of the first. How does the power

radiated from the second compare to the first?

a. 10 times

b. 16 times

c. 25 times

d. 400 times

66. A wall consists of a 10. cm thick layer of brick (0.84 J/s-m-C), then a

1.3 cm thickness of wood (0.1 J/s-m-C), 10 cm of fiberglass (0.048 J/s-m-

C), and a final 1.3 cm layer of wood. How much heat conducts through

30 m2 area of this wall if the temperature difference across the wall is

36° F? a. 0.14 KW

b. 0.28 KW

c. 0.42 KW

d. none of these

67. Lead melts at 227° C. Its specific heat is 130 J/kg-C and heats of fusion

and vaporization 0.25 x 105 J/kg and 8.7 x 105 J/kg respectively. How much heat is required to heat up and melt 4.0 kg of lead originally at

20° C? a. 3.5 MJ

b. 2.7 MJ

c. 0.72 MJ

d. 0.16 MJ

68. A single food CALORIE is enough energy to raise 1.0 kg how high?

a. 43 cm

b. 72 cm

c. 0.43 Km

d. 0.72 Km

69. An ideal gas undergoing a "free expansion":

a. does positive work

b. increases its internal energy

c. decreases its internal energy

d. does not change its internal energy

70. The sun transfers heat to the planets primarily by:

a. conduction

b. forced convection

c. radiation

d. natural convection

71. One hundred grams of steam at 100° C is cooled to form ice at -10° C. How much energy was released?

a. 7.29 x 104 cal

b. 7.29 x 104 J

c. 7.19 x 104 cal

d. 7.19 x 104 J

72. Which graph represents an isothermal process?

a. A

b. B

c. C

d. D

73. Which of the following is not a heat engine:

a. gasoline engine

b. the Carnot cycle

c. gas stove

d. refrigerator operated in reverse

74. An engine takes in 4.7 calories of heat and discharges 3.5 calories of

heat. What is its efficiency?

a. 26%

b. 33%

c. 74%

d. 134%

75. A Carnot engine takes in 4.7 heat calories at 1000° C and has an efficiency of 37%. It discharges heat at what lower temperature?

a. 630° C b. 630 K

c. 529 K

d. 529° C

76. Bill drops a 50 gram (0° C) ice cube into a large pond which is at 20° C. What is the total entropy change of the total process?

a. 3.7 J/K

b. 4.7 J/K

c. 5.4 J/K

d. 76. J/K

ANSWER KEY

1. b

2. b

3. b

4. d

5. c

6. c

7. a

8. b

9. a

10. d

11. a

12. a

13. d

14. b

15. c

16. d

17. c

18. a

19. c

20. c

21. a

22. a

23. d

24. b

25. a

26. a

27. d

28. a

29. b

30. b

31. c

32. d

33. b

34. d

35. d

36. d

37. b

38. False

39. b

40. b

41. d

42. c

43. b

44. a

45. b

46. a

47. d

48. d

49. c

50. b

51. d

52. a

53. a

54. c

55. b

56. d

57. d

58. c

59. c

60. b

61. a

62. a

63. c

64. b

65. d

66. a

67. d

68. d

69. d

70. c

71. a

72. b

73. c

74. a

75. d

76. b

METRIC PREFIXES

Prefix: Symbol: Magnitude:

Yotta- Y 1024

Zetta- Z 1021

Exa- E 1018

Peta- P 1015

Tera- T 1012

Giga- G 109

Mega- M 106

myria- my 104

kilo- k 103

hecto- h 102

deka- da 10

Prefix: Symbol: Magnitude:

deci- d 10-1

centi- c 10-2

milli- m 10-3

micro- 10-6

nano- n 10-9

pico- p 10-12

femto- f 10-15

atto- a 10-18

zepto- z 10-21

yocto- y 10-24