Physics for Scientists and Engineers, 4e (Giancoli)

Physics for Scientists and Engineers, 4e (Giancoli) Chapter 2 Describing Motion: Kinematics in One Dimension 2.1 Conceptual Questions 1) Car A is traveling at twice the speed of car B. They both hit the brakes at the same time and undergo identical decelerations. How does the time required for car A to stop compare with that for car B? Answer : Car A takes twice as long to stop. Diff: 1 Page Ref: Sec. 2-5 2) Car A is traveling at twice the speed of car B. They both hit the brakes at the same time and undergo identical decelerations. How does the distance required for car A to stop compare with that for car B? Answer : It takes four times the distance to stop. Diff: 1 Page Ref: Sec. 2-5 3) It is possible to have a zero acceleration, and still be moving. Answer : TRUE Diff: 1 Page Ref: Sec. 2-4 4) When the velocity and acceleration of an object have the same sign, the speed of the object increases. Answer : TRUE Diff: 1 Page Ref: Sec. 2-4 5) When the velocity and acceleration of an object have opposite signs, the speed of the object increases. Answer : FALSE Diff: 1 Page Ref: Sec. 2-4 6) The average velocity of a car traveling with a constant acceleration during a certain time interval is equal to the mean of the velocities at the beginning and end of that time interval. Answer : TRUE Diff: 1 Page Ref: Sec. 2-5 7) Suppose that an object travels from one point in space to another. Make a comparison between the displacement and the distance traveled. A) The displacement is either greater than or equal to the distance traveled. B) The displacement is always equal to the distance traveled. C) The displacement is either less than or equal to the distance traveled. D) The displacement can be either greater than, smaller than, or equal to the distance traveled. E) If the displacement is equal to zero, then the distance traveled will also equal zero. Answer : C Diff: 1 Page Ref: Sec. 2-1 8) Which statement below about the distance between the starting and ending positions and the displacement between the starting and ending positions is correct? A) The distance between the starting and ending positions is twice the magnitude of the displacement between the starting and ending positions. B) The distance between the starting and ending positions is equal to the magnitude of the displacement between the starting and ending positions. C) The distance between the starting and ending positions is the negative of the magnitude of the displacement between the starting and ending positions. D) The distance between the starting and ending positions is greater than the magnitude of the displacement between the starting and ending positions. E) The distance between the starting and ending positions is less than the magnitude of the displacement between the starting and ending positions. Answer : B Diff: 1 Page Ref: Sec. 2-1 9) Which statement is correct about the relationship between the average speed and the magnitude of the average velocity for any motion? A) The average speed is always one-half the magnitude of the average velocity. B) The average speed is always greater than or equal to the magnitude of the average velocity. C) The average speed can be less than, greater than or equal to the magnitude of the average velocity. D) The average speed is always less than or equal to the magnitude of the average velocity. E) The average speed is always equal to the magnitude of the average velocity. Answer : B Diff: 1 Page Ref: Sec. 2-2 10) Which statement is correct about the relationship between the instantaneous speed and the magnitude of the instantaneous velocity? A) The average speed can be less than, greater than or equal to the magnitude of the average velocity. B) The instantaneous speed is always equal to the magnitude of the instantaneous velocity. C) The average speed is always less than or equal to the magnitude of the average velocity. D) The instantaneous speed is always greater than or equal to the magnitude of the instantaneous velocity. E) The average speed is always one-half the magnitude of the average velocity. Answer : B Diff: 1 Page Ref: Sec. 2-3 11) The slope of a line connecting two points on a position versus time graph gives A) displacement. B) instantaneous velocity. C) average velocity. D) instantaneous acceleration. E) average acceleration. Answer : C Diff: 1 Page Ref: Sec. 2-3 12) The slope of a tangent line at a given time value on a position versus time graph gives A) displacement. B) instantaneous velocity. C) average velocity. D) instantaneous acceleration. E) average acceleration Answer : B Diff: 1 Page Ref: Sec. 2-3 13) If the position versus time graph of an object is a horizontal line, the object is A) moving with constant non-zero speed. B) moving with constant non-zero acceleration. C) at rest. D) moving with infinite speed. E) none of the above Answer : C Diff: 1 Page Ref: Sec. 2-3 14) If the position versus time graph of an object is a vertical line, the object is A) moving with constant non-zero speed. B) moving with constant non-zero acceleration. C) at rest. D) moving with infinite speed. E) none of the above Answer : D Diff: 1 Page Ref: Sec. 2-3 15) When is the average velocity of an object equal to the instantaneous velocity? A) always B) never C) only when the velocity is constant D) only when the velocity is increasing at a constant rate E) only when the velocity is decreasing at a constant rate Answer : C Diff: 2 Page Ref: Sec. 2-3 FIGURE 2-1 16) Fig. 2-1 shows the position of an object as a function of time. During which time interval is the object at rest between 0.0 s and 9.0 s? A) The object is at rest between 6.0 s and 9.0 s. B) The object is always at rest except at the instants t = 3.0 s and t = 6.0 s. C) The object is at rest between 0.0 s and 3.0 s. D) The object is at rest between 3.0 s and 6.0 s. E) The object is never at rest. Answer : D Diff: 2 Page Ref: Sec. 2-3 17) Suppose that an object is moving with a constant velocity. Make a statement concerning its acceleration. A) The acceleration must be constantly increasing. B) The acceleration must be constantly decreasing. C) The acceleration must be a constant non-zero value. D) The acceleration must be equal to zero. E) A statement cannot be made without additional information. Answer : D Diff: 1 Page Ref: Sec. 2-4 18) Suppose that an object is moving with constant acceleration. Which of the following is an accurate statement concerning its motion? A) In equal times its speed changes by equal amounts. B) In equal times its velocity changes by equal amounts. C) In equal times it moves equal distances. D) The object is not moving; it is at rest. E) A statement cannot be made without additional information. Answer : B Diff: 1 Page Ref: Sec. 2-4 19) At a given instant, the acceleration of a certain particle is zero. This means that A) the velocity is constant. B) the velocity is increasing. C) the velocity is decreasing. D) the velocity is not changing at that instant. E) the velocity is zero. Answer :