Motion Review Multiple Choice Identify the choice that best completes the statement or answers the question. 1. When an object’s distance from another object is 8. If speed is measured in kilometers per hour and changing, time is measured in hours, the unit of acceleration a. it is in motion. is b. it is speeding. a. hours. c. it has a high velocity. b. kilometers per hour. d. it is accelerating. c. kilometers per hour per hour. d. kilometers. 2. Speed equals distance divided by a. time. 9. Average speed is b. velocity. a. equivalent to velocity. c. size. b. the rate at which an object is moving at a given d. motion. instant. c. the rate at which a slope changes. 3. When you know both the speed and direction of an d. the total distance traveled divided by the total object’s motion, you know the time. a. average speed of the object. b. acceleration of the object. 10. On a graph showing distance versus time, a c. distance the object has traveled. horizontal line represents an object that is d. velocity of the object. a. moving at a constant speed. b. increasing its speed. 4. You can show the motion of an object on a line c. decreasing its speed. graph in which you plot distance against d. not moving at all. a. velocity. b. time. 11. If you know the distance an object has traveled in a c. speed. certain amount of time, you can determine d. direction. a. the size of the object. b. the speed of the object. 5. The rate at which velocity changes is called c. the location of the object. a. instantaneous speed. d. the acceleration of the object. b. direction. c. acceleration. 12. If the speed of an object does NOT change, the d. motion. object is traveling at a a. constant speed. 6. Which of these is an example of deceleration? b. average speed. a. a bird taking off for flight c. increasing speed. b. a roller coaster moving down a steep hill d. decreasing speed. c. a car approaching a red light d. an airplane following a straight flight path 13. Changing direction is an example of a kind of a. acceleration. 7. To determine the acceleration rate of an object, you b. speed. must calculate the change in speed during each unit c. velocity. of d. constant rate. a. velocity. b. time. 14. If a bicyclist travels 30 kilometers in two hours, her c. motion. average speed is d. deceleration. a. 30 km/h. b. 60 km/h. c. 15 km/h. d. 2 km/h. 15. The moon accelerates because it is a. in a vacuum in space. b. continuously changing direction. c. a very large sphere. d. constantly increasing its speed of orbit. 17. If you know a car traveled 300 kilometers in 3 hours, you can find its a. acceleration. b. direction. c. average speed. d. velocity. 16. If an object moves in the same direction and at a constant speed for 4 hours, which of the following is true? a. The object’s speed changed during the 4 hours. b. The object’s velocity did not change. c. The object accelerated during the 4 hours. d. The object decelerated during the 4 hours. 18. In an acceleration graph showing speed versus time, a straight line shows the acceleration is a. decreasing. b. increasing. c. changing. d. constant. Completion Complete each statement. 19. A change in an object’s position relative to a reference point is called ____________________. 20. When riding a bicycle past a building, you are not moving relative to the ____________________. 21. The distance traveled by a moving object per unit of time is called ____________________. 22. The statement that the motion of a hurricane is 20 kilometers per hour in an easterly direction is a description of the hurricane’s ____________________. Short Answer 23. Acceleration is the rate of change in ____________________. 24. A golf ball ____________________ when either its speed or direction changes. 25. The motion of a car stopping at a traffic light is an example of a(n) ____________________ acceleration, also called deceleration. Use the diagram to answer each question. 26. What two variables are plotted in the graph? 27. How would you describe Kathy’s motion? What does such motion mean? 28. How far did Kathy jog in the first 4 minutes? 30. How long after Kathy started jogging did Rachel begin jogging? 29. What is Kathy’s average speed? 31. Describe Rachel’s motion at 9 minutes. Use the diagram to answer each question. 32. What two variables are plotted in the graph? 33. What does the line segment on the graph from 0 to 3 seconds represent? Explain your answer. 34. What is the acceleration of the ball between 0 and 3 seconds? Essay 38. You are riding in a car traveling at 80 km/h. A fly trapped in the car rests on your shoulder. Describe the speed of the fly using two different reference points. 39. People living at Earth’s equator are traveling at a speed of about 1,670 km/h as Earth spins on its axis. Are these people being accelerated? Explain. 40. Car A is traveling north at 30 m/s and car B is traveling south at 30 m/s. If both cars have a southward acceleration of 1 m/s2, compare their speeds after 1 second. Explain your comparison. 35. What happened to the speed of the ball during the final two seconds? 36. Does the graph indicate that the ball decelerated? Explain your answer. 37. How far did the ball move in the final 2 seconds? Motion Review Answer Section MULTIPLE CHOICE 1. ANS: A 2. ANS: A 3. ANS: D 4. ANS: B 5. ANS: C 6. ANS: C 7. ANS: B 8. ANS: C 9. ANS: D 10. ANS: D 11. ANS: B 12. ANS: A 13. ANS: A 14. ANS: C 15. ANS: B 16. ANS: B 17. ANS: C 18. ANS: D COMPLETION PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 DIF: DIF: DIF: DIF: DIF: DIF: DIF: DIF: DIF: DIF: DIF: DIF: DIF: DIF: DIF: DIF: DIF: DIF: L1 L1 L1 L1 L1 L2 L1 L2 L1 L2 L1 L1 L2 L2 L2 L2 L2 L2 REF: REF: REF: REF: REF: REF: REF: REF: REF: REF: REF: REF: REF: REF: REF: REF: REF: REF: p. M-7 p. M-10 p. M-12 p. M-14 p. M-22 p. M-23 p. M-24 p. M-24 p. M-11 p. M-15 p. M-10 p. M-11 p. M-22 p. M-11 p. M-23 p. M-12 p. M-11 p. M-26 19. ANS: motion 20. ANS: bicycle 21. ANS: speed 22. ANS: velocity 23. ANS: speed 24. ANS: accelerates 25. ANS: negative SHORT ANSWER 26. ANS: distance and time 27. ANS: Kathy is jogging at a constant speed. Her speed does not change as she moves. 28. ANS: 600 m 29. ANS: Average speed = distance/time = 1,500 m/10 min = 150 m/min 30. ANS: 2 minutes 31. ANS: Rachel is not moving; she is at rest. 32. ANS: speed and time 33. ANS: The segment represents constant acceleration. The speed increases by the same amount during each second. 34. ANS: 1 m/s2 (3m/s – 0 m/s)/3 s = (3 m/s)/(3 s) = (1 m/s)/s = 1 m/s2 35. ANS: The ball’s speed was constant; it did not change. 36. ANS: No. Deceleration is a negative acceleration, which means an object slows down. According to the graph, the ball’s velocity increased in the first three seconds and then remained the same for the next 2 seconds. It did not slow down. Deceleration would be indicated by a line that slopes downward. 37. ANS: 6 m (3.0 m/s 2 s = 6 m) ESSAY 38. ANS: From the reference point of Earth, the fly is moving at a speed of 80 km/h, the same as the car. From the reference point of the car or your shoulder, the speed of the fly is 0 km/h because it is not moving with respect to the car or your shoulder. 39. ANS: They are being accelerated because the direction of their motion is constantly changing as they spin in a circle. 40. ANS: After 1 second, Car A’s speed is 29 m/s and car B’s speed is 31 m/s. For northbound Car A, a southward acceleration is a deceleration, or negative acceleration. For car A to have a negative acceleration, its final velocity must be less than its initial velocity. So car A slows down by 1 m/s in 1 second of travel. Southbound car B speeds up by 1 m/s in 1 second of travel.