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Topic #04 Graphical Analysis of Motion

Word Problems

 Topic #04 Concepts and Skills Link to "Concepts and Skills"

 Vocabulary, Variables and Equations All vocabulary used in Topics 1, 2 and 3

 Review Questions: Chapter 5 Review Concepts Questions: Section 5.1 1. A walker and a runner leave your front door at the same time.  They move in the same direction at different constant velocities.  Describe the position-time graphs of each. 2. What does the slope of the tangent to the curve on a position-time graph measure? Section 5.2 3. If you know the position of an object at two points along its path, and you also know the time it took to get from one point to the other, can you determine the particle’s instantaneous velocity?  Its average velocity?  Explain. 4. What quantity is represented by the area under a velocity-time curve? 5. Figure 5-20 shows the velocity-time graph for an automobile on a test track.  Describe how the velocity changes with time. Section 5.3 6. What does the slope of the tangent to the curve on a velocity-time graph measure? 7. A car is traveling on an interstate highway. a. Can the car have a negative velocity and a positive acceleration at the same time?  Explain. b. Can the car’s velocity change signs while it is traveling with constant acceleration?  Explain. 8. Can the velocity of an object change when its acceleration is constant?  If so, give an example.  If not, explain. 9. If the velocity-time curve is a straight line parallel to the t-axis, what can you say about the acceleration? 10. If you are given a table of velocities of an object at various times, how could you find out if the acceleration of the object is constant? 11. Write a summary of the equations for position, velocity, and time for an object experiencing uniformly accelerated motion. Section 5.4 12. Explain why an aluminum ball and a steel ball of similar size and shape, dropped from the same height, reach the ground at the same time. 13. Give some examples of the falling objects for which air resistance cannot be ignored. 14. Give some examples of falling objects for which air resistance can be ignored.

 Application Questions: Chapter 5 Questions 15. (Figure 5-20) shows the velocity-time graph of an accelerating car. The three “notches” in the curve occur where the driver changes gears.   a. Describe the changes in velocity and acceleration of the car while in first gear.   b. Is the acceleration just before a gear change larger or smaller than the acceleration just after the change?  Explain your answer. 16. Explain how you would walk to produce each of the position-time graphs in (Figure 5-21). 17. Use (Figure5-20) to determine during what time interval the acceleration is largest and during what time interval the acceleration is smallest. 18. Solve the equation v = v[0] + at for acceleration. 19. Figure 5-22 is a position-time graph of two people running.   a. Describe the position of runner A relative to runner B at the y-intercept.   b. Which runner is faster?   c. What occurs at point P and beyond? 20 Figure 5-23 is a position-time graph of the motion of two cars on a road.   a. At what time(s) does one car pass the other?   b. Which car is moving faster at .0s?   c. At what time(s) do the cars have the same velocity?   d. Over what time interval is car B speeding up all the time?   e. Over what time interval is car B slowing down all the time? 21. Look at Figure 5-24.   a. What kind of motion is represented by a?   b. What does the area under the curve represent?   c. What kind of motion is represented by b?   d. What does the area under the curve represent? 22. An object shot straight up rises for 7.0S before it reaches its maximum height.  A second object falling from rest takes 7.l0s to reach the ground.  Compare the displacements of the two objects during this time interval. 23.Describe the changes in the velocity of a ball thrown straight up into the air.  Then describe the changes in the ball's acceleration. 24. The value of g on the moon is 1/6 of its value on Earth. 25. Planet Dweeb has three times the gravitational acceleration of Earth.  A ball is thrown vertically upward with the same initial velocity on Earth and on Dweeb   a. How does the maximum height reached by the ball on Dweeb compare to the maximum height on Earth?   b. If the ball on Dweeb were thrown with three times greater initial velocity, how would that affect your answer to a? 26. Rock A is dropped from a cliff; rock B is thrown upwards from the same position.   a. When they reach the ground at the bottom of the cliff, which rock has a greater velocity?   b. Which has a greater acceleration.   c. Which arrives first?

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