# Chapter 3 Practice Problems, Review, and Assessment SOLUTION: 2. Use the v-t graph of the toy train in Figure 9 to answer these questions.

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1 Section 1 Acceleration: Practice Problems 1. The velocity-time graph in Figure 8 describes Steven s motion as he walks…

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chapter 3 Practice Problems, Review, and Assessment

Section 1 acceleration : Practice Problems 1. The velocity-time graph in Figure 8 describes Steven ’ south gesticulate as he walks along the center at the state fair. Sketch the corresponding gesticulate diagram. Include speed vectors in your diagram.

solution :

2. Use the v-t graph of the dally coach in Figure 9 to answer these questions.

a. When is the train ’ s travel rapidly constant ? b. During which time interval is the educate ’ sulfur acceleration positivist ? c. When is the string ’ s acceleration most negative ? solution : a. 5.0 to 15.0 randomness bel. 0.0 to 5.0 s c. 15.0 to 20.0 mho 3. Refer to Figure 9 to find the average acceleration of the caravan during the stick to time intervals.

a. 0.0 sulfur to 5.0 sulfur b. 15.0 sulfur to 20.0 randomness eSolutions Manual – Powered by Cognero c. 0.0 second to 40.0 s solution :

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SOLUTION : a. 5.0 to 15.0 s chapter 3 Practice barn. 0.0 to 5.0 randomness Problems, Review, and Assessment c. 15.0 to 20.0 randomness 3. Refer to Figure 9 to find the average acceleration of the string during the take after time intervals.

a. 0.0 second to 5.0 randomness b. 15.0 south to 20.0 s c. 0.0 sulfur to 40.0 mho solution :

4. CHALLENGE Plot a v-t graph representing the follow motion : An elevator starts at rest from the ground deck 2

of a three-story shopping promenade. It accelerates up for 2.0 sulfur at a rate of 0.5 m/s, continues up at a ceaseless 2 speed of 1.0 m/s for 12.0 mho, and then slows down with a constant down acceleration of 0.25 m/s for 4.0 sulfur as it reaches the third deck. solution :

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Chapter 3 Practice Problems, Review, and Assessment 4. CHALLENGE Plot a v-t graph representing the following apparent motion : An elevator starts at perch from the background floor 2

of a three-story patronize plaza. It accelerates upward for 2.0 s at a pace of 0.5 m/s, continues up at a ceaseless 2 speed of 1.0 m/s for 12.0 s, and then slows down with a constant downward acceleration of 0.25 m/s for 4.0 sulfur as it reaches the third floor. solution :

5. A race car ’ s forward speed increases from 4.0 m/s to 36 m/s over a 4.0-s time time interval. What is its median acceleration ? solution :

6. The subspecies car in the previous trouble slows from 36 m/s to 15 m/s over 3.0 s. What is its average acceleration ? solution :

7. A bus is moving west at 25 m/s when the driver steps on the brakes and brings the bus to a barricade in 3.0 s. a. What is the average acceleration of the bus while braking ? b. If the bus took twice equally long to stop, how would the acceleration compare with what you found in share a ? solution : a.

2 b. half as great ( 4.2 m/s east ) 8. A car is coasting backward downhill at a speed of 3.0 m/s when the driver gets the engine started. After 2.5 sulfur, the car is moving uphill at 4.5 m/s. If uphill is chosen as the positive direction, what is the cable car ’ south average acceleration ? solution :

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3 Practice Problems, Review, and Assessment Chapter 2 b. half as great ( 4.2 m/s east ) 8. A car is coasting backward downhill at a accelerate of 3.0 m/s when the driver gets the locomotive started. After 2.5 mho, the car is moving uphill at 4.5 m/s. If acclivitous is chosen as the positive direction, what is the car ’ s average acceleration ? solution :

9. Rohith has been jogging east toward the bus stop at 3.5 m/s when he looks at his determine and sees that he has enough of time before the bus arrives. Over the adjacent 10.0 mho, he slows his pace to a easy 0.75 m/s. What was his average acceleration during this 10.0 south ? solution :

10. CHALLENGE If the rate of continental drift were to abruptly slow from 1.0 cm/y to 0.5 cm/y over the time time interval of a year, what would be the modal acceleration ? solution :

Section 1 Acceleration : review 11. MAIN IDEA What are three ways an object can accelerate ? solution : accelerate up, slow down, transfer focus 12. Position-Time and Velocity-Time Graphs Two joggers run at a changeless speed of 7.5 m/s east. figure 10 shows the positions of both joggers at time thymine = 0. a. What would be the difference ( sulfur ) in the position-time graph of their motion ? bacillus. What would be the difference ( mho ) in their velocity-time graph ?

solution : page 4 a. Both lines would have the lapp gradient, but they would rise from the x-axis at different points, +15 thousand, and −15 m. bel. Their velocity-time graph would be identical.

Section 1 Acceleration : review 11. MAIN IDEA What are three ways an object can accelerate ? SOLUTION : chapter 3 Practice Review, and Assessment speed up, slowProblems, down, change steering 12. Position-Time and Velocity-Time Graphs Two joggers run at a ceaseless speed of 7.5 m/s east. figure 10 shows the positions of both joggers at time thyroxine = 0. a. What would be the deviation ( s ) in the position-time graph of their motion ? b. What would be the difference ( mho ) in their velocity-time graph ?

solution : a. Both lines would have the same slope, but they would rise from the x-axis at different points, +15 megabyte, and −15 m. barn. Their velocity-time graph would be identical. 13. Velocity-Time Graph Sketch a velocity-time graph for a car that goes east at 25 m/s for 100 s, then west at 25 m/s for another 100 s. SOLUTION :

14. average Velocity and Average Acceleration A canoeist paddles upstream at a speed of 2.0 m/s for 4.0 s and then floats downriver at 4.0 m/s for 4.0 s. a. What is the median speed of the canoe during the 8.0-s time time interval ? bel. What is the median acceleration of the canoe during the 8.0-s clock interval ? solution : a. Choose a coordinate system with the positive direction upstream.

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Chapter 3 Practice Problems, Review, and Assessment 14. average Velocity and Average Acceleration A canoeist paddles upriver at a speed of 2.0 m/s for 4.0 s and then floats downstream at 4.0 m/s for 4.0 s. a. What is the average speed of the canoe during the 8.0-s time time interval ? b-complex vitamin. What is the average acceleration of the canoe during the 8.0-s time time interval ? solution : a. Choose a coordinate system with the convinced steering upriver.

barn.

15. critical Thinking A patrol officeholder clocked a driver going 32 kilometers per hour over the accelerate limit good as the driver passed a slower car. When the policeman stopped the car, the driver argued that the other driver should get a ticket deoxyadenosine monophosphate well. The driver said that the cars must have been going the like travel rapidly because they were observed adjacent to each early. Is the driver correct ? Explain with a sketch and a apparent motion diagram. solution : No, the cars had the same place, not speed. To have the like speed, they would have had to have the same relative military position for a distance of time.

Section 2 Motion with changeless acceleration : Practice Problems 16. A golf ball rolls up a hill toward a miniature-golf hole. Assume the direction toward the hole is positive.

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Chapter 3 Practice Problems, Review, and Assessment 15. critical Thinking A police officer clocked a driver going 32 kilometers per hour over the accelerate specify just as the driver passed a slower cable car. When the policeman stopped the car, the driver argued that the other driver should get a ticket vitamin a good. The driver said that the cars must have been going the same speed because they were observed next to each other. Is the driver correct ? Explain with a sketch and a gesture diagram. solution : No, the cars had the like position, not speed. To have the same speed, they would have had to have the like relative position for a length of time.

Section 2 Motion with constant acceleration : Practice Problems 16. A golf ball rolls up a mound toward a miniature-golf hole. Assume the direction toward the fix is positive. a. If the golf ball starts with a speed of 2.0 m/s and slows at a constant rate of 0.50 m/s2, what is its speed after 2.0 s ? b. What is the golf ball ’ s speed if the constant acceleration continues for 6.0 s ? c. Describe the motion of the golf ball in words and with a motion diagram. solution : a. vf = six + at 2 = +2.0 m/s + ( −0.50 m/s ) ( 2.0 s ) = +1.0 m/s b. vf = six + at 2 = +2.0 m/s + ( −0.50 m/s ) ( 6.0 mho ) = − 1.0 m/s c. The musket ball ’ s speed decreased in the first case. In the irregular, the ball slowed to a barricade and then began rolling back down the hill.

2

17. A bus traveling at 30.0 kilometers per hour east has a constant increase in speed of 3.5 m/s. What speed does it reach 6.8 sulfur page 7 late ?

SOLUTION :

chapter 3 Practice Problems, Review, and Assessment 2

17. A bus traveling at 30.0 kilometers per hour east has a constant increase in speed of 3.5 m/s. What speed does it reach 6.8 second late ? solution :

2

18. If a car accelerates from pillow at a changeless rate of 5.5 m/s north, how hanker will it take for the car to reach a speed of 28 m/s north ? solution :

2

19. CHALLENGE A cable car slows from 22 m/s to 3.0 m/s at a constant rate of 2.1 m/s. How many seconds are required before the cable car is traveling at a forth speed of 3.0 m/s ? solution : Let the forward commission be positive.

20. The graph in Figure 13 describes the movement of two bicyclists, Akiko and Brian, that start from remainder and change of location north, increasing their amphetamine with a constant acceleration. What was the sum shift of each cyclist during the prison term shown for each ? trace : Use the area of a triangle : area = ( 1/2 ) ( free-base ) ( acme ).

solution : eSolutions by Cognero Δx Manual = 9.0- Powered m north ; Δx =

A

B

8.0 m union

21. The motion of two people, Carlos and Diana, moving confederacy along a straight path is described by the graph in

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Chapter 3 Practice Problems, Review, and Assessment 20. The graph in Figure 13 describes the motion of two bicyclists, Akiko and Brian, that start from rest and travel north, increasing their speed with a constant acceleration. What was the total translation of each cyclist during the time shown for each ? touch : Use the sphere of a triangle : sphere = ( 1/2 ) ( base ) ( height ).

solution : Δx A = 9.0 megabyte north ; Δx B = 8.0 m north 21. The apparent motion of two people, Carlos and Diana, moving south along a straight path is described by the graph in Figure 14. What is the sum supplanting of each person during the 4.0-s interval shown on the graph ?

solution : Δx C = 8.0 molarity south ; Δx D = 4.0 m confederacy 22. CHALLENGE A car, equitable pulling onto a directly stretch of highway, has a ceaseless acceleration from 0 m/s to 25 m/s west in 12 s. a. Draw a v-t graph of the car ’ s apparent motion. b. Use the graph to determine the car ’ s supplanting during the 12.0-s time interval. c. Another car is traveling along the same stretch of highway. It travels the same distance in the like time as the first car, but its speed is changeless. Draw a v-t graph for this cable car ’ randomness motion. d. Explain how you knew this cable car ’ randomness speed. solution : a.

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SOLUTION : chapter 3 Practice Problems, Review, and Assessment Δx C = 8.0 megabyte south ; Δx D = 4.0 m south 22. CHALLENGE A cable car, merely pulling onto a straight stretch of highway, has a ceaseless acceleration from 0 m/s to 25 m/s west in 12 s. a. Draw a v-t graph of the car ’ south motion. b-complex vitamin. Use the graph to determine the car ’ s displacement during the 12.0-s time interval. c. Another car is traveling along the same stretch of highway. It travels the same outdistance in the same clock time as the first cable car, but its speed is constant. Draw a v-t graph for this cable car ’ sulfur gesture. d. Explain how you knew this car ’ s speed. solution : a.

bacillus. The displacement is the area under the velocity-time graph.

speed of light.

d. The translation was the same for both cars. For the second car, then, v = Δx / thyroxine = 150 thousand ÷ 12 s = 13 molarity west ( rounding to the right number of meaning figures ). 23. A skateboarder is moving at a ceaseless accelerate of 1.75 m/s when she starts up an slope that causes her to slow 2 down with a constant acceleration of −0.20 m/s. How much time passes from when she begins to slow down until she begins to move back down the slope ? eSolutions Manual – Powered by Cognero

SOLUTION :

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d. The displacement was the sameand for both cars. For the second gear car, then, v = Δx / triiodothyronine = 150 megabyte ÷ 12 mho = 13 chapter 3 Practice Problems, Review, Assessment m west ( rounding to the discipline count of significant figures ). 23. A skateboarder is moving at a ceaseless accelerate of 1.75 m/s when she starts up an tend that causes her to slow 2 down with a changeless acceleration of −0.20 m/s. How much time passes from when she begins to slow down until she begins to move back down the incline ? solution :

24. A race car travels on a straight racetrack with a forward speed of 44 m/s and slows at a ceaseless rate to a speed of 22 m/s over 11 s. How far does it move during this prison term ? solution : Let the convinced direction be fore.

25. A car accelerates at a constant rate from 15 m/s to 25 m/s while it travels a distance of 125 m. How long does it take to achieve the final speed ? solution :

26. A bicycle rider pedals with constant acceleration to reach a speed of 7.5 m/s north over a fourth dimension of 4.5 s. During the period of acceleration, the bicycle ’ sulfur translation is 19 meter north. What was the initial speed of the bicycle ? solution :

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Chapter 3 Practice Problems, Review, and Assessment 26. A bicycle rider pedals with changeless acceleration to reach a speed of 7.5 m/s north over a time of 4.5 s. During the time period of acceleration, the bicycle ’ s translation is 19 molarity north. What was the initial speed of the bicycle ? solution :

2

27. CHALLENGE The cable car in Figure 16 travels west with a forward acceleration of 0.22 m/s. What was the car ’ south speed ( six ) at bespeak eleven if it travels a distance of 350 m in 18.4 sulfur ?

solution :

2

28. A car with an initial speed of 24.5 m/s east has an acceleration of 4.2 m/s west. What is its displacement at the moment that its speed is 18.3 m/s east ? solution :

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29. A homo runs along the path shown in Figure 17. From bespeak A to point B, he runs at a forward speed of 4.5 m/s

chapter 3 Practice Problems, Review, and Assessment 2

28. A car with an initial speed of 24.5 m/s east has an acceleration of 4.2 m/s west. What is its displacement at the moment that its speed is 18.3 m/s east ? solution :

29. A man runs along the path shown in Figure 17. From point A to distributor point B, he runs at a forward speed of 4.5 m/s 2 for 15.0 min. From point B to point C, he runs up a hill. He slows down at a constant rate of 0.050 m/s for 90.0 s and comes to a stop at point C. What was the total distance the man ran ?

solution :

2

30. You start your bicycle ride at the top of a hill. You coast down the hill at a constant acceleration of 2.00 m/s. When you get to the bottom of the hill, you are moving at 18.0 m/s, and you pedal to maintain that amphetamine. If you continue at this focal ratio for 1.00 min, how far will you have gone from the time you left the hilltop ? solution :

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Chapter 3 Practice Problems, Review, and Assessment 2

30. You start your bicycle ride at the exceed of a hill. You coast down the mound at a ceaseless acceleration of 2.00 m/s. When you get to the penetrate of the mound, you are moving at 18.0 m/s, and you pedal to maintain that accelerate. If you continue at this travel rapidly for 1.00 min, how far will you have gone from the time you left the hilltop ? solution :

31. Sunee is training for a 5.0-km raceway. She starts out her prepare run by moving at a changeless tempo of 4.3 m/s for 19 minute. then she accelerates at a changeless rate until she crosses the finish line 19.4 sulfur later. What is her acceleration during the last helping of the discipline run ? solution :

32. CHALLENGE Sekazi is learning to ride a bicycle without train wheels. His don pushes him with a constant 2 acceleration of 0.50 m/s east for 6.0 s. Sekazi then travels at 3.0 m/s east for another 6.0 sulfur before falling. What is eSolutions Manual – Powered by Cognero Page 14 Sekazi ’ s displacement ? Solve this problem by constructing a velocity-time graph for Sekazi ’ s motion and computing the sphere underneath the graph telephone line.

chapter 3 Practice Problems, Review, and Assessment 32. CHALLENGE Sekazi is learning to ride a bicycle without train wheels. His church father pushes him with a constant 2 acceleration of 0.50 m/s east for 6.0 s. Sekazi then travels at 3.0 m/s east for another 6.0 s before falling. What is Sekazi ’ sulfur displacement ? Solve this problem by constructing a velocity-time graph for Sekazi ’ s apparent motion and computing the area underneath the graph note. solution :

Section 2 Motion with changeless acceleration : review 33. MAIN IDEA If you were given initial and final examination velocities and the changeless acceleration of an object, and you were asked to find the displacement, what mathematical relationship would you use ? solution : 2

2

vf = six + 2aΔx 34. acceleration A womanhood driving west along a straight road at a speed of 23 m/s sees a deer on the road ahead. She applies the brakes when she is 210 thousand from the deer. If the deer does not move and the cable car stops veracious before it hits the deer, what is the acceleration provided by the cable car ’ second brakes ? solution : Let the positive focus be west.

2

35. Distance The airplane in Figure 18 starts from respite and accelerates east at a constant 3.00 m/s for 30.0 second before leaving the land. a. What was the plane ’ south displacement ( Δx ) ? bel. How fast was the airplane going when it took off ? eSolutions Manual – Powered by Cognero

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Chapter 3 Practice Problems, Review, and Assessment 2

35. Distance The airplane in Figure 18 starts from rest and accelerates east at a changeless 3.00 m/s for 30.0 south before leaving the ground. a. What was the plane ’ randomness displacement ( Δx ) ? bacillus. How flying was the airplane going when it took off ?

solution : a. Let the positive focus be east.

b. vf = united states virgin islands + atf 2

= 0.0 m/s + ( 3.00 m/s ) ( 30.0 mho ) = 90.0 m/s 36. Distance An in-line skater first accelerates from 0.0 m/s to 5.0 m/s in 4.5 mho, then continues at this ceaseless amphetamine for another 4.5 s. What is the total distance traveled by the in-line skater ? solution :

Final Velocity

2

37. manual – Powered A plane travels a distance of 5.0×10 eSolutions by Cognero 2

rate of 5.0 m/s. What final examination speed does it attain ? solution :

m union while being accelerated uniformly from rest at the Page 16

Chapter 3 Practice Problems, Review, and Assessment 2

37. Final Velocity A plane travels a outdistance of 5.0×10 m north while being accelerated uniformly from rest at the 2

rate of 5.0 m/s. What final speed does it attain ? solution :

2

38. Final Velocity An airplane accelerated uniformly from rest at the rate of 5.0 m/s confederacy for 14 s. What final speed did it attain ? SOLUTION : 2

vf = six + atf = 0 m/s + ( 5.0 m/s ) ( 14 second ) 1

= 7.0×10 m/s south 39. Graphs A sprinter walks up to the begin blocks at a constant speed and positions herself for the start of the race. She waits until she hears the start pistol go off and then accelerates quickly until she attains a constant speed. She maintains this speed until she crosses the end line, and then she slows to a walk, taking more meter to slow down than she did to speed up at the begin of the rush. Sketch a velocity-time and a position-time graph to represent her motion. Draw them one above the early using the like meter scale. Indicate on your position-time graph where the start blocks and coating course are. solution :

40. critical Thinking Describe how you could calculate the acceleration of an automobile. Specify the measure instruments and the procedures you would use. solution : One person reads a stopwatch and calls out time intervals. Another person reads the speedometer at each clock time and records it. Plot speed versus clock time and find the gradient.

incision 3 rid drop : Practice Problems 41. A construction actor unintentionally drops a brick from a high scaffold. a. What is the speed of the brick after 4.0 s ? during this meter ?

eSolutions Manualfar – Powered by brick Cognero b. How does the fall

SOLUTION : a. Let up be the positive commission.

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SOLUTION : chapter Practice Problems, Review, Assessment One3person reads a stopwatch andand calls out prison term intervals. Another person reads the speedometer at each time and records it. Plot speed versus time and find the gradient.

section 3 detached fall : Practice Problems 41. A construction worker unintentionally drops a brick from a eminent scaffold. a. What is the speed of the brick after 4.0 south ? b. How far does the brick fall during this clock time ? solution : a. Let up be the cocksure guidance.

bel.

The brick falls 78 m. 42. Suppose for the previous problem you choose your coordinate system so that the inverse steering is positive. a. What is the brick ’ south speed after 4.0 south ? b-complex vitamin. How army for the liberation of rwanda does the brick fall during this time ? solution : a. now the plus direction is down. vf = united states virgin islands + at, a = 9.8 m/s2

vf = 0.0 m/s + ( 9.8 m/s2 ) ( 4.0 south ) = +39 m/s = 39 m/s up b-complex vitamin.

43. A student drops a ball from a window 3.5 megabyte above the sidewalk. How flying is it moving when it hits the sidewalk ? solution :

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Chapter 3 Practice Problems, Review, and Assessment 43. A scholar drops a ball from a window 3.5 thousand above the sidewalk. How firm is it moving when it hits the sidewalk ? solution :

44. A tennis ball is thrown square up with an initial accelerate of 22.5 m/s. It is caught at the same distance above the ground. a. How high does the testis wax ? b. How long does the ball remain in the air ? tip : The time it takes the ball to rise equals the meter it takes to fall. solution : a.

barn.

45. You decide to flip a coin to determine whether to do your physics or English homework inaugural. The mint is flipped straight up. a. What is the speed of the coin at the top of its trajectory ? b. If the mint reaches a high distributor point of 0.25 m above where you released it, what was its initial accelerate ? c. If you catch it at the like stature as you released it, how much time did it spend in the publicize ? solution : a. vtop = 0 m/s ; a top = 9.8 m/s down b. eSolutions Manual – Powered by Cognero

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Chapter 3 Practice Problems, Review, and Assessment 45. You decide to flip a coin to determine whether to do your physics or English homework first gear. The coin is flipped directly astir. a. What is the speed of the coin at the top of its trajectory ? b. If the coin reaches a high point of 0.25 m above where you released it, what was its initial amphetamine ? c. If you catch it at the lapp stature as you released it, how much time did it spend in the air ? solution : a. vtop = 0 m/s ; a lead = 9.8 m/s downward b.

coke.

46. CHALLENGE A basketball player is holding a ball in her hands at a height of 1.5 m above the earth. She drops the ball, and it bounces respective times. After the first bounce, the ball lone returns to a height of 0.75 m. After the moment bounce, the ball lone returns to a height of 0.25 m. a. Suppose downward is the cocksure direction. What would the shape of a velocity-time graph spirit like for the first two bounces ? b. What would be the condition of a position-time graph for the first two bounces ? solution : a. The velocity-time graph would be straight pipeline segments that begin at the beginning and then rise, fall, and resurrect again. b. The graph would start at the origin and have an inverted parabolic condition.

Section 3 Free fall : inspection 47. MAIN IDEA Suppose you hold a book in one hand and a compressed sheet of newspaper in another hand. You drop them both, and they fall to the ground. Explain why the falling book is a good example of spare descend, but the newspaper is not. solution : complimentary fall is the motion of an aim when graveness is the only significant force on it. The newspaper is significantly affected by the air, but the book is not. 48. final Velocity Your baby drops your house keys polish to you from the second gear floor window, as shown in Figure 25. What is the speed of the keys when you catch them ? eSolutions Manual – Powered by Cognero

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and they fall to the ground. Explain why the falling script is a good model of dislodge fall, but the newspaper is not. solution : spare fall is the apparent motion of an object when graveness is the only meaning military unit on it. The paper is Chapter 3 Practiceaffected Problems, Review, and significantly by the air, but theAssessment koran is not. 48. final Velocity Your sister drops your house keys down to you from the second floor window, as shown in Figure 25. What is the speed of the keys when you catch them ?

solution : Let up be the positive direction.

49. Free-Fall Ride Suppose a free-fall ride at an amusement park starts at rest and is in free fall. What is the speed of the drive after 2.3 s ? How far do people on the ride fall during the 2.3-s clock time time period ? solution :

Let up be the convinced management.

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50. maximum Height and Flight Time The free-fall acceleration on Mars is about one-third that on Earth. Suppose you throw a ball up with the same speed on Mars as on Earth.

chapter 3 Practice Problems, Review, and Assessment 49. Free-Fall Ride Suppose a free-fall ride at an amusement ballpark starts at remainder and is in complimentary fall. What is the speed of the ride after 2.3 randomness ? How far do people on the drive drop during the 2.3-s prison term menstruation ? solution :

Let up be the positive commission.

50. maximum Height and Flight Time The free-fall acceleration on Mars is about one-third that on Earth. Suppose you throw a ball upward with the lapp speed on Mars as on Earth. a. How would the ball ’ s maximum height comparison to that on Earth ? b-complex vitamin. How would its fledge fourth dimension compare ? SOLUTION :

a. Let M = Mars and E = Earth. At maximum acme, vf = 0, so

The utmost acme would be three times higher on Mars. boron.

Flight time is three times longer on Mars. 51. speed and Acceleration Suppose you throw a ball straight improving into the air. Describe the changes in the speed of the testis. Describe the changes in the acceleration of the testis. solution : speed is reduced at a constant rate as the musket ball travels up. At its highest point, speed is nothing. As the ball begins to drop, the speed begins to increase in the negative commission. When it reaches the acme from which it was initially released, the ball has the lapp speed it had upon release. The eSolutions Manual – Powered by Cognero Page 22 acceleration is constant throughout the ball ’ randomness flight. 52. critical Thinking A ball throw vertically up continues up until it reaches a sealed position and then

3 Practice Problems, Review, and Assessment Chapter Flight meter is three times longer on Mars. 51. speed and Acceleration Suppose you throw a ball straight up into the tune. Describe the changes in the speed of the ball. Describe the changes in the acceleration of the ball. solution : speed is reduced at a ceaseless pace as the ball travels up. At its highest distributor point, speed is zero. As the ball begins to drop, the speed begins to increase in the damaging direction. When it reaches the height from which it was initially released, the ball has the same accelerate it had upon handout. The acceleration is constant throughout the ball ’ randomness trajectory. 52. critical Thinking A ball throw vertically upward continues up until it reaches a certain position and then falls down. The ball ’ mho speed is instantaneously zero at that highest point. Is the ball accelerating at that point ? Devise an experiment to prove or disprove your answer. solution : sample answer : The ball is accelerating ; its speed is changing. Take a multiflash photograph to measure its position. From photograph, calculate the ball ’ sulfur speed.

Chapter Assessment Section 1 acceleration : Mastering Concepts 53. BIG IDEA How are speed and acceleration related ? solution : acceleration is the exchange in speed divided by the time interval in which it occurs. It is the rate of switch of speed. 54. Give an model of each of the follow : a. an object that is slowing down, but has a plus acceleration b. an object that is speeding up but has a negative acceleration c. an object that is moving at a constant accelerate but has an acceleration solution : a. if forward is the positive commission, a car moving back at decreasing speed b. in the like coordinate arrangement, a car moving backward at increasing amphetamine c. a car that is moving on a circular track at a constant speed 55. figure 26 shows the velocity-time graph for an car on a test track. Describe how the speed changes with time.

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SOLUTION : The car starts from rest and increases its rush. As the cable car ’ s speed increases, the driver shift gears.

SOLUTION : a. if forward is the positive direction, a car moving backward at decreasing speed Chapter Practice Problems, Review, b. in3 the lapp align system, aand carAssessment moving back at increasing speed c. a car that is moving on a round traverse at a constant rush 55. figure 26 shows the velocity-time graph for an automobile on a test track. Describe how the speed changes with clock time.

SOLUTION : The car starts from perch and increases its accelerate. As the cable car ’ s travel rapidly increases, the driver shift gears. 56. If the velocity-time graph of an object move on a straight path is a line parallel to the horizontal axis, what can you conclude about the object ’ mho acceleration ? solution : When the velocity-time graph is a line parallel to the horizontal axis, the acceleration is zero.

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