Type:
Test Bank
Resource:
College Physics Explore and Apply
Edition:
2nd Edition
Author(s):
Eugenia Etkina Gorazd Planinsic Alan Van Heuvelen
TEST BANK
COLLEGE PHYSICS S ECOND E DITION Eugenia Etkina Rutgers University
Matthew Blackman Ridge High School and Rutgers New Brunswick
Gorazd Planinsic University of Ljubljana, Slovenia
Alan Van Heuvelen Rutgers University
Table of Contents Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6
Introduction ....................................................................................................... 1-1 Kinematics: Motion in One Dimension ............................................................ 2-1 Newtonian Mechanics ....................................................................................... 3-1 Applying Newton’s Laws ................................................................................. 4-1 Circular Motion ................................................................................................. 5-1 Impulse and Linear Momentum ........................................................................ 6-1
Chapter 7 Chapter 8
Work and Energy .............................................................................................. 7-1 Extended Bodies at Rest ................................................................................... 8-1
Chapter 9 Chapter 10 Chapter 11 Chapter 12 Chapter 13 Chapter 14 Chapter 15
Rotational Motion ............................................................................................. 9-1 Vibrational Motion.......................................................................................... 10-1 Mechanical Waves .......................................................................................... 11-1 Gases ............................................................................................................... 12-1 Static Fluids .................................................................................................... 13-1 Fluids in Motion.............................................................................................. 14-1 First Law of Thermodynamics ........................................................................ 15-1
Chapter 16 Chapter 17 Chapter 18 Chapter 19 Chapter 20 Chapter 21 Chapter 22
Second Law of Thermodynamics ................................................................... 16-1 Electric Charge, Force and Energy ................................................................. 17-1 The Electric Field ............................................................................................ 18-1 DC Circuits ..................................................................................................... 19-1 Magnetism....................................................................................................... 20-1 Electromagnetic Induction .............................................................................. 21-1 Reflection and Refraction ............................................................................... 22-1
Chapter 23 Chapter 24
Mirrors and Lenses ......................................................................................... 23-1 Wave Optics .................................................................................................... 24-1
Chapter 25 Chapter 26 Chapter 27 Chapter 28 Chapter 29 Chapter 30
Electromagnetic Waves .................................................................................. 25-1 Special Relativity ............................................................................................ 26-1 Quantum Optics .............................................................................................. 27-1 Atomic Physics ............................................................................................... 28-1 Nuclear Physics ............................................................................................... 29-1 Particle Physics ............................................................................................... 30-1
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College Physics: Explore and Apply, 2e (Etkina, Planinsic, and Van Heuvelen) Chapter 1 Introduction 1.1 Conceptual Questions 1) In the product A, B, and C, the quantity A has 5 significant figures, B has 2 significant figures, and C has 3 significant figures. How many significant figures does the product have? A) 10 B) 5 C) 4 D) 3 E) 2 Answer: E 2) In the quotient
, the quantity A has 5 significant figures, B has 2 significant figures, and C
has 3 significant figures. How many significant figures does the quotient have? A) 2 B) 3 C) 4 D) 0 E) 1 Answer: A 3) How many significant figures are in the number 0.0037010? A) eight B) seven C) six D) five E) four Answer: D 4) How many significant figures are in the number 0.010? A) four B) three C) two D) one Answer: C 5) How many significant figures are in the number 120.070? A) three B) four C) five D) six Answer: D
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6) The number of significant figures in 10001 is A) two B) three C) five D) six Answer: C 7) The number of significant figures in 0.01500 is A) two B) three C) four D) five Answer: C 8) The number of significant figures in 0.040 is A) one B) two C) three D) four Answer: B 9) Which of the following numbers has 4 significant figures; which has 5 significant figures? A) 3001 B) 0.00370 C) 4774.00 D) 29.290 Answer: (A) has 4 significant figures; (D) has 5 significant figures 10) In a parallel universe, the quantity π has the value 3.14049. Express π in that universe to (A) four significant figures (B) five significant figures Answer: (A) 3.140; (B) 3.1405 11) A reasonable estimate for the mass of a typical female college student is A) 300 kg B) 200 kg C) 150 kg D) 50 kg E) 20 kg Answer: D 12) A reasonable estimate for the height of an ordinary adult male is A) 50 cm B) 70 cm C) 200 cm D) 300 cm Answer: C 2 ..
13) A reasonable estimate for the mass of a typical new-born baby is A) 1 kg B) 3 kg C) 10 kg D) 20 kg Answer: B 14) A reasonable estimate for the height of the walls of a room in an ordinary American home is A) 10 m B) 8 m C) 2.5 m D) 1.5 m Answer: C 15) A reasonable estimate for the duration of a typical physics lecture is A) 600 s B) 1000 s C) 3500 s D) 10,000 s Answer: C 16) A reasonable estimate for the mass of an ordinary passenger car is A) 100 kg B) 1000 kg C) 5000 kg D) 10,000 kg Answer: B 1.2 Problems 1) What is the product of 12.56 and 2.12 expressed to the correct number of significant figures? A) 27 B) 26.6 C) 26.23 D) 26.627 Answer: B 2) What is the quotient of 2.43 ÷ 4.561 expressed to the correct number of significant figures? A) 5.3278 × 10-1 B) 5.328 × 10-1 C) 5.33 × 10-1 D) 5.3 × 10-1 Answer: C
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3) What is
expressed to the correct number of significant figures?
A) 0.9 B) 0.91 C) 0.911 D) 0.9108 Answer: B 4) The length and width of a rectangle are 1.125 m and 0.606 m, respectively. Multiplying, your calculator gives the product as 0.68175. Rounded properly to the correct number of significant figures, the area of the rectangle should be written as A) 0.68 m2 B) 0.682 m2 C) 0.6818 m2 D) 0.68175 m2 Answer: B 5) The last page of a book is numbered 764. The book is 3.0 cm thick, not including its covers. What is the average thickness (in centimeters) of a page (a leaf) in the book, rounded to the proper number of significant figures? A) 0.0039 cm B) 0.00393 cm C) 0.00785 cm D) 0.0079 cm E) 0.072 cm Answer: D 6) A rectangular garden measures 15 m long and 13.70 m wide. What is the length of a diagonal from one corner of the garden to the opposite corner? A) 18 m B) 19 m C) 20 m D) 4.1 × 102 m Answer: C 7) If a circle has a radius of 1.109 m, what is its area, expressed to the correct number of significant figures? A) 3.86 m2 B) 3.863 m2 C) 3.86379 m2 D) 3.8638 m2 E) 3.864 m2 Answer: E
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8) From a digital balance, the mass of a certain piece of wood is read as 12.946 g. Thinking in terms of accuracy and significant figures, what value would you record on your data sheet if the balance is accurate to one-tenth of a gram? A) 12.9 g B) 12.95 g C) 13 g D) 13.0 g Answer: A 9) Which of the following numbers is the smallest? A) 15 × 10-3 B) 0.15 × 100 C) 0.00015 × 103 D) 0.00000015 × 106 Answer: A 10) Which one of the following numbers is equivalent to the number 0.0001776? A) 17.76 × 10-3 B) 1.776 × 10-4 C) 1776 × 10-5 D) 177.6 × 10-7 Answer: B 11) Write out the number 8.42 × 10-5 in full with a decimal point and correct number of zeros. A) 0.00000842 B) 0.0000842 C) 0.000842 D) 0.00842 Answer: B 12) What is the result of the calculation (0.410 + 0.021) × (2.20 × 103)? A) 880 B) 946 C) 948 D) 950 Answer: C 13) Express (2.2 × 106)-1/2 in scientific notation. A) 1.5 × 10-5 B) 6.7 × 10-4 C) 1.5 × 103 D) 1.5 × 104 Answer: B
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14) Express the number 13.5 gigameters in meters without using scientific notation. A) 135,000 m B) 135,000,000 m C) 135,000,000,000 m D) 13,500,000,000 m Answer: D 15) A volume of 100 mL is equivalent to which one of the following volumes? A) 1 kl B) 10-6 μl C) 0.01 ml D) 0.1 L Answer: D 16) The volume of a 10-ml test tube is equivalent to which one of the following quantities? A) 1 × 10-6 L B) 0.001 kl C) 0.1 L D) 0.01 L E) 0.001 ml Answer: D 17) The number 0.00325 × 10-8 cm can be expressed in millimeters as A) 3.25 × 10-12 mm B) 3.25 × 10-11 mm C) 3.25 × 10-10 mm D) 3.25 × 10-9 mm Answer: C 18) The prefix yotta (Y) signifies a multiple of 1024. How many yottameters are there in a gigameter? Answer: 10-15 Ym 19) The quantity 0.00325 × 10-8 mm is equivalent to A) 3.25 × 10-12 cm B) 3.25 × 10-11 cm C) 3.25 × 10-10 cm D) 3.25 × 10-9 cm E) 3.25 × 10-8 cm Answer: A
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20) A weight lifter can bench press 171 kg. How many milligrams is this? A) 1.71 × 109 mg B) 1.71 × 108 mg C) 1.71 × 107 mg D) 1.71 × 106 mg Answer: B 21) How many nanoseconds (ns) does it take for a computer to perform one calculation if it performs 6.7 × 107 calculations per second? A) 11 ns B) 15 ns C) 65 ns D) 67 ns Answer: B 22) A certain CD-ROM disk can store 600 megabytes of information. If an average word requires 9.0 bytes of storage, how many words can be stored on one disk? A) 6.7 × 107 words B) 5.4 × 109 words C) 2.1 × 107 words D) 2.0 × 109 words Answer: A 23) The wavelength of the light from a certain laser is 0.66 microns, where 1 micron = 1.0 × 106 m. What is this wavelength in nanometers? (1 nm = 10-9 m) A) 6.6 × 102 nm B) 6.6 × 103 nm C) 6.6 × 101 nm D) 6.6 × 104 nm Answer: A 24) The mass of Mars, 6.40 × 1023 kg, is about one-tenth that of Earth, and its radius, 3395 km, is about half that of Earth. What is the mean density (mass divided by volume) of Mars in kilograms per cubic meter? A) 9.76 × 102 kg/m3 B) 1.95 × 103 kg/m3 C) 3.90 × 103 kg/m3 D) 7.81 × 103 kg/m3 Answer: C
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25) Estimate how many pennies you would have to stack to reach from the floor to an average 8ft ceiling. A) 2 × 106 B) 2 × 105 C) 2 × 104 D) 2 × 103 E) 2 × 102 Answer: D 26) Estimate the number of times the earth will rotate on its axis during a human's lifetime. A) 3 × 108 B) 3 × 107 C) 3 × 106 D) 3 × 105 E) 3 × 104 Answer: E 27) Estimate the thickness, in meters, of an ordinary sheet of paper. A) 10-8 m B) 10-7 m C) 10-6 m D) 10-5 m E) 10-4 m Answer: E 28) Which of the following is the most reasonable estimate of the number of characters (typed letters or numbers) in a 194-page book? Assume an average of 600 words per page and a reasonable average number of letters per word. A) 5 × 105 characters B) 5 × 107 characters C) 5 × 106 characters D) 5 × 104 characters Answer: A 29) A marathon race is 26 mi and 385 yd long. Estimate how many strides would be required to run a marathon. Assume a reasonable value for the average number of feet/stride. A) 4.5 × 104 strides B) 4.5 × 103 strides C) 4.5 × 105 strides D) 4.5 × 106 strides Answer: A
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30) Estimate the number of times an average person's heart beats in a lifetime. Assume the average heart rate is 69 beats/min and a life span of 75 years. A) 3 × 109 beats B) 3 × 108 beats C) 3 × 1010 beats D) 3 × 107 beats Answer: A
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College Physics: Explore and Apply, 2e (Etkina, Planinsic, and Van Heuvelen) Chapter 2 Kinematics: Motion in One Dimension 2.1 Conceptual Questions
1) A bowling ball rolls over a smooth horizontal floor with constant velocity. Four students (Antonio, Bela, Charles, and Dominique) are presented with the measured position-versus-time data shown on the graph above, and are asked to calculate the velocity of the ball. Each of the students takes a different approach, drawing the lines shown in red below, and calculating the slope of these lines.
Which student's analysis will result in the most accurate calculation of the ball's velocity during the six-second time interval shown? A) Antonio B) Bela C) Charles D) Dominique Answer: D
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The following questions refer to the following material. A diagram representing the motion of two cars is shown below. The number near each dot indicates the clock reading in seconds when the car passes that location.
2) At which instant(s) in time do the cars have the same horizontal position? A) 1 s B) 1 s, 2 s, and 3 s C) 1 s, 3 s, and 5 s D) 1 s, 2 s, 3 s, and 5 s E) never Answer: A 3) At which instant(s) in time do the cars have the same velocity? A) 1 s B) 1 s, 2 s, and 3 s C) 1 s, 3 s, and 5 s D) 1 s, 2 s, 3 s, and 5 s E) never Answer: E 4) Which of the following is true about the average acceleration of Car 1 and the acceleration of Car 2 during the time interval shown? A) Car 1's average acceleration is nonzero and twice that of Car 2. B) Car 2's average acceleration is nonzero and twice that of Car 1. C) Car 1's average acceleration is nonzero and equal to that of Car 2. D) Both cars have an average acceleration of zero. Answer: D
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5) The figure above shows a motion diagram for an object. The number near each dot indicates the clock reading in seconds when the object passes that location. The positive direction is defined as to the right of the page. Which of the following is true about the object? A) The object has the greatest magnitude acceleration at t = 3 s. B) The object has positive acceleration for the entire time interval. C) The object has negative acceleration for the entire time interval. D) The object has positive acceleration before t = 3 s and negative acceleration after t = 3 s. E) The object has negative acceleration before t = 3 and positive acceleration after t = 3 s. Answer: E 6) Which of the following must be true of an object that is slowing down? A) Its acceleration must be negative. B) Its velocity must be smaller than its acceleration. C) Its velocity must be larger than its acceleration. D) Its velocity and its acceleration must be in opposite directions. E) Its velocity must be negative. Answer: D 7) An object is shot vertically upward on the surface of the Earth with a positive initial velocity. Which of the following correctly describes the velocity and acceleration of the object at its maximum elevation, taking the positive direction as upward? Velocity Acceleration A) Positive Positive B) Zero Zero C) Negative Negative D) Zero Negative E) Positive Negative Answer: D 8) You throw a small ball upward and notice the time it takes to come back. If you then throw the same ball so that it takes twice as much time to come back, what is true about the motion of the ball the second time? A) Its initial speed was twice the speed in the first experiment. B) Its initial speed was less than twice the speed in the first experiment. C) Its initial speed was more than twice, but less than four times the speed in the first experiment. D) Its initial speed was more than four times the speed in the first experiment. Answer: A 3 ..
9) You throw a small ball upward and measure the upward distance that it travels to its peak. If you then throw the same ball so that it travels twice the upward distance to its peak, what is true about the motion of the ball the second time? A) Its initial speed was twice the speed in the first experiment. B) Its initial speed was less than twice the speed in the first experiment. C) Its initial speed was more than twice, but less than four times the speed in the first experiment. D) Its initial speed was four times the speed in the first experiment. E) Its initial speed was more than four times the speed in the first experiment. Answer: B 10) You throw a small ball upward and notice the time it takes to come back. If you then throw the same ball so that it takes twice as much time to come back, what is true about the motion of the ball the second time? A) It had half as much acceleration on the way up as it did the first time. B) It had the same acceleration on the way up as it did the first time. C) It had twice as much acceleration on the way up as it did the first time. D) It had more than twice as much acceleration on the way up as it did the first time. Answer: B 11) In the absence of air resistance, an object dropped near the surface of the Earth moves with a constant acceleration of 9.8 m/s2 downwards. This means that A) the speed of the object increases by 9.8 m/s during each second. B) the speed of the object increases by 9.8 m/s during the first second only. C) the speed of the object as it falls is 9.8 m/s. D) the object falls 9.8 meters during each second. E) the object falls 9.8 meters during the first second only. Answer: A 12) When a ball is thrown straight up with no air resistance, the acceleration of the ball at its highest point A) is downward B) is upward C) is zero D) reverses from upward to downward E) reverses from downward to upward Answer: A
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13) A girl is standing on top of a building, initially holding a baseball and a softball. She simultaneously does something to each ball, causing each to undergo the motion represented by the velocity-versus-time graph above. What does the girl do? Select two answers. A) Throws the baseball upward. B) Throws the baseball downward. C) Throws the softball upward. D) Throws the softball downward. Answer: B, C
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The following questions apply to the motion diagrams below. The positive direction is to the right of the page.
14) Which of the dot diagrams above represents the motion of an object that has a positive velocity and a negative acceleration? A) A B) B C) C D) D E) E Answer: C 15) Which of the dot diagrams above represents the motion of an object that has a negative velocity and a negative acceleration? A) A B) B C) C D) D E) E Answer: E
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16) Which of the motion diagrams above represents an object whose position as a function of time is shown on the graph below?
A) A B) B C) C D) D E) E Answer: B
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17) A position-versus-time graph for a point-like object is shown above. In which of the lettered graphs below does the object have the same average velocity as in the above graph for the time interval t = 0 to t = 5 s? A)
B)
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C)
D)
E)
Answer: B
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18) A position-versus-time graph for a point-like object is shown above. In which of the lettered graphs below does the object have the same average speed as in the above graph for the time interval t = 0 to t = 5s? A)
B)
C)
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D)
E)
Answer: E
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19) Which position-versus-time graph shown below represents the motion of an object that is moving in the negative direction and slowing down? A)
B)
C)
D)
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E)
Answer: C
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20) Which position-versus-time graph shown below represents the motion of an object that is moving in the negative direction and speeding up? A)
B)
C)
D)
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E)
Answer: B
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21) A bungee jumper drops from rest off a bridge, and is in freefall for half of the distance to the ground. Her cable then kicks in, and she slows down at a constant acceleration for the other half of the distance. Which of the following graphs could represent her position as a function of time during the time interval described? A)
B)
C)
D)
E)
Answer: A
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22) When is the object represented by the graph above moving in the positive direction? A) from t = 0 s to t = 4 s only B) from t = 8 s to t = 10 s only C) from t = 0 s to t = 3 s and from t = 6 s to t = 8 s D) at t = 4 s and t = 10 s Answer: A
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23) Which of the following velocity-versus-time graphs depicts an object remaining at rest? A)
B)
C)
D)
E)
Answer: A 18 ..
24) You have two small metal spheres. You drop the first sphere and throw the second one in the upward direction. Which of the following statements are correct about their motion? Select two answers. A) The second sphere will spend less time in flight. B) The first sphere will have a slower final speed when it reaches the ground. C) The second sphere will have larger acceleration. D) Both spheres will have the same acceleration. Answer: B, D
25) The graph above represents the velocity as a function of time for an object moving along a straight line. Which of the following is true at t = 4 s? Select two answers. A) The object is moving in the negative direction. B) The object is moving in the positive direction. C) The object is instantaneously at rest. D) The object is changing acceleration. E) The object is changing direction. Answer: B, D
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26) Above is a position-versus-time graph for an object. Which is a correct description of the object's motion? A) The object rolls along a flat surface. It then rolls down a hill, and finally stops. B) The object does not move at first. Then it rolls down a hill, and keeps going. C) The object is moving at a constant velocity. Then it slows down and stops. D) The object does not move at first. Then it moves at a constant velocity, and stops. E) The object moves along a flat surface. Then it rolls down a hill, and keeps going. Answer: D
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27) The graph shown above represents an object that is doing which of the following? A) moving down a hill at a constant speed B) moving at a constant velocity in the negative direction C) moving in the negative direction and slowing down D) speeding up in the negative direction Answer: D
28) A cart is released from rest on a uniform ramp, shown above. It takes the Car 2 seconds to roll all the way to the bottom of the ramp. Where is the Car located at t = 1 second? A) to the left of the halfway point B) at the halfway point C) to the right of the halfway point D) Cannot be determined Answer: A 29) An object that is thrown straight upward in free fall on Earth will have an acceleration of magnitude A) 9.8 m/s2 on the way up and less than 9.8 m/s2 on the way down B) 9.8 m/s2 on the way up and more than 9.8 m/s2 on the way down C) More than 9.8 m/s2 on the way up and 9.8 m/s2 on the way down D) Less than 9.8 m/s2 on the way up and 9.8 m/s2 on the way down E) 9.8 m/s2 on the way up and 9.8 m/s2 on the way down Answer: E
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30) A car speeds up from rest, and then maintains a constant nonzero velocity. Which of the following position-versus-time graphs represents the motion of the car? A)
B)
C)
D)
E)
Answer: C
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31) A bicycle is moving at a constant velocity in the positive direction, and then slows down until it is stopped. Which of the following velocity-versus-time graphs represents the motion of the bicycle? A)
B)
C)
D)
E)
Answer: A 23 ..
32) The velocity-versus-time graph for an object is shown above. At which clock reading is the object changing its direction of motion? A) A B) B C) C D) D E) E Answer: C
33) The graph shown above represents an object that is doing which of the following? A) Speeding up in the positive direction B) Slowing down, then speeding up C) Moving in the positive direction and slowing down D) Speeding up in the negative direction, then speeding up in the positive direction Answer: C
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34) A cheetah is initially moving in the positive direction, but slowing down with a constant acceleration. Which of the following is true about the distance traveled by the cheetah? A) The cheetah travels the same distance between the instants 0 and 1 s as it does between the times 1 and 2 s. B) The cheetah travels less distance between the times 0 and 1 s than between the times 1 and 2 s. C) The cheetah travels a greater distance between the times 0 and 1 s than between the times 1 and 2 s. D) Not enough information. Answer: C 35) An object has a negative acceleration. Which is true about the motion of the object? A) It is moving at a constant speed. B) It is speeding up. C) It is slowing down. D) It is turning around. E) Not enough information. Answer: E
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The following questions refer to the graph shown below, which represents the velocity of an object as a function of time.
36) At which time is the object changing direction? A) 3 s B) 5 s C) 6 s D) 7 s E) The object is never changing direction during the time interval shown. Answer: B 37) At which time after t = 0 s will the object be found back at its starting position? A) At t = 3 s B) At t = 5 s C) At t = 6 s D) Never during the time interval shown on the graph Answer: D 38) During which time interval(s) is the object moving in negative direction? A) From t = 3 s to t = 5 s B) From t = 3 s to t = 6 s C) From t = 5 s to t = 6 s D) From t = 5 s to t = 8 s E) From t = 3 s to t = 8 s Answer: D
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The following questions refer to the graph shown below, which represents the position of an object as a function of time.
39) At which time is the object changing direction? A) 2 s B) 4 s C) 6 s D) 7 s E) The object is never changing direction during the time interval shown. Answer: A 40) At which instant in time after t = 0 s will the object be found back at its starting position? A) At t = 2 s B) At t = 4 s C) At t = 6 s D) Never during the time interval graphed Answer: B 41) At which time interval(s) is the object slowing down? A) From t = 0 s to t = 2 s B) From t = 0 s to t = 4 s C) From t = 4 s to t = 6 s D) From t = 2 s to t = 6 s E) From t = 0 s to t = 2 s and from t = 4 s to t = 6 s Answer: E
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42) Which of these position-versus-time graphs represents an object moving at a constant nonzero velocity? A)
B)
C)
D)
E)
Answer: B
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43) Which of the following velocity-versus-time graphs represents an object that is speeding up at a uniform rate of acceleration? A)
B)
C)
D)
E)
Answer: D
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44) The acceleration-versus-time graphs for five point-like objects are shown below. Which object has the smallest change in velocity during the given time interval? A)
B)
C)
D)
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E)
Answer: D
45) The displacement x of an object moving along the x-axis is shown as a function of time t. The acceleration must be A) zero B) constant but not zero C) increasing D) decreasing Answer: A
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46) Two cars are initially 400 m apart, moving toward each other on a straight road. The graphs to the right represent the cars' velocities as a function of time. When will the cars be located at the same position? A) At t = 10 s B) At t = 20 s C) At t = 30 s D) At t = 40 s E) At t = 50 s Answer: A
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47) The velocity-versus-time graph above could represent the motion of which of the following objects? A) A ball is thrown straight upward. It reaches the peak of its flight, and comes back down. B) A ball is rolling horizontally at a constant rate. It bounces from a wall, and continues to move at a constant rate in the opposite direction. C) A ball is rolling horizontally while slowing down. It bounces from a wall, and continues to slow down while moving in the opposite direction. D) A ball is released from rest. It bounces off from the ground, and reaches its peak again after bouncing. Answer: D 48) Consider a deer that runs from point A to point B. The path length traveled by the deer can be greater than the magnitude of the deer's displacement, but the magnitude of the deer's displacement can never be greater than the path length traveled. A) True B) False Answer: A 49) Which of the following quantities has units of a displacement? (There could be more than one correct choice.) A) 32 ft/s2 vertically downward B) 40 km southwest C) 9.8 m/s2 D) -120 m/s E) 186,000 mi Answer: B, E
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50) Suppose that an object travels from one point in space to another. Make a comparison between the magnitude of the object's displacement and the path length traveled by the object. A) The displacement is either greater than or equal to the path length traveled. B) The displacement is always equal to the path length traveled. C) The displacement is either less than or equal to the path length traveled. D) The displacement can be either greater than, smaller than, or equal to the path length traveled. Answer: C 51) Consider a car that travels between points A and B. The car's average speed can be greater than the magnitude of its average velocity, but the magnitude of its average velocity can never be greater than its average speed. A) True B) False Answer: A 52) Which of the following quantities has units of a velocity? (There could be more than one correct choice.) A) 40 km southwest B) -120 m/s C) 9.8 m/s2 downward D) 186,000 mi E) 9.8 m/s downward Answer: B, E 53) When is the average velocity of an object equal to the instantaneous velocity throughout a particular time interval? A) when the velocity is increasing at a constant rate throughout the time interval B) when the velocity is decreasing at a constant rate throughout the time interval C) when the velocity is constant throughout the time interval D) always E) never Answer: C 54) You drive 6.0 km at 50 km/h and then another 6.0 km at 90 km/h. Your average speed over the 12 km drive will be A) greater than 70 km/h B) equal to 70 km/h C) less than 70 km/h D) exactly 38 km/h E) It cannot be determined from the information given because we must also know directions traveled. Answer: C
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55) If the instantaneous velocity of an object is zero at some instant in time, then its acceleration must also be zero at that instant. A) True B) False Answer: B 56) Which of the following situations is impossible? A) An object's instantaneous velocity is directed east and its acceleration is directed west. B) An object's instantaneous velocity is directed east and its acceleration is also directed east. C) An object's instantaneous velocity is directed east and its acceleration is zero. D) An object's instantaneous velocity is zero and it acceleration is directed east. E) All of the above are possible. Answer: E 57) If an object has an acceleration of zero, then that object must also have an instantaneous velocity of zero. A) True B) False Answer: B 58) If the instantaneous velocity of an object is zero, then that object must also have zero acceleration. A) True B) False Answer: B 59) Suppose that a car traveling to the west slows down as it approaches a traffic light. Which of the following statements about its acceleration is correct? A) The acceleration is toward the east. B) The acceleration is toward the west. C) The acceleration is zero. D) The direction of the acceleration cannot be determined. Answer: A 60) An auto manufacturer advertises that their car can go "from zero to sixty miles per hour in eight seconds." This specifies what characteristic of the car's motion? A) average speed B) instantaneous speed C) average acceleration D) instantaneous acceleration E) displacement Answer: C
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