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Import Settings: Base Settings: Brownstone Default Information Field: Difficulty Information Field: SectionDef Highest Answer Letter: E Multiple Keywords in Same Paragraph: No Chapter: Chapter 3 Multiple Choice 1. A park ranger wanted to measure the height of a tall tree. The ranger stood 9.50 m from the base of the tree; and he observed that his line of sight made an angle of 65.2° above the horizontal as he looked at the top of the tree. The park ranger's eyes are 1.80 m above the ground. What is the height of the tree? A) 5.84 m B) 8.77 m C) 11.7 m D) 17.3 m E) 22.4 m Ans: E Difficulty: Easy SectionDef: Section 3-1 2. A toolbox is carried from the base of a ladder at point A as shown in the figure. The toolbox comes to a rest on a scaffold 5.0 m above the ground. What is the magnitude of the displacement of the toolbox in its movement from point A to point B? A) 15 m B) 19 m

C) 8.1 m D) 11 m E) 13 m Ans: E Difficulty: Easy SectionDef: Section 3-1 3. A delivery truck leaves a warehouse and travels 2.60 km north. The truck makes a left turn and travels 1.25 km west before making another right turn to travel 1.40 km north to arrive at its destination. What is the magnitude and direction of the truck's displacement from the warehouse? A) 4.00 km, 18.2° north of west B) 5.25 km, 59.8° north of west C) 6.33 km, 70.2° north of west D) 3.40 km, 55.0° north of west E) 4.19 km, 72.6° north of west Ans: E Difficulty: Medium SectionDef: Section 3-1 4. A car travels due east at 22 m/s. It makes a turn due south and continues to travel at 22 m/s. What is the change in velocity of the car? A) 22 m/s, due east B) 22 m/s, due south C) 31 m/s, 45° south of west D) 31 m/s, 45° south of east E) zero m/s Ans: C Difficulty: Medium SectionDef: Section 3-1 5. A train travels due south at 60 m/s. It reverses its direction and travels due north at 60 m/s. What is the change in velocity of the train?

Reference: Ref 3-1 During a one-hour trip, a small boat travels 80.0 km north and then travels 60.0 km east. 8. What is the boat's displacement for the one-hour trip? A) 20 km B) 100 km C) 140 km D) 280 km E) 10 000 km Ans: B Refer To: Ref 3-1 Difficulty: Easy SectionDef: Section 3-1 9. What is the boat's average speed during the one-hour trip? A) 20 km/h B) 100 km/h C) 140 km/h D) 280 km/h E) 10 000 km/h Ans: C Refer To: Ref 3-1 Difficulty: Medium SectionDef: Section 3-1 10. What is the magnitude of the boat's average velocity for the one-hour trip? A) 20 km/h B) 100 km/h

C) 140 km/h D) 10 000 km/h E) 20 000 km/h Ans: B Refer To: Ref 3-1 Difficulty: Medium SectionDef: Section 3-1 11. What is the direction of the boat's average velocity for the one-hour trip? A) due east B) 36.9° north of east C) 41.7° north of east D) 49.2° north of east E) 53.1° north of east Ans: E Refer To: Ref 3-1 Difficulty: Medium SectionDef: Section 3-1 12. An eagle is flying due east at 8.9 m/s carrying a gopher in its talons. The gopher manages to break free at a height of 12 m. What is the magnitude of the gopher's velocity as it reaches the ground? Note: effects of air resistance are not included in this calculation. A) 22 m/s B) 18 m/s C) 11 m/s D) 9.8 m/s E) 8.9 m/s Ans: B Difficulty: Medium SectionDef: Section 3-2 and Section 3-3 13. At time t = 0 s, a puck is sliding on a horizontal table with a velocity 3.60 m/s, 35.0° above the + x axis. As the puck slides, a constant acceleration acts on it that has the following

C) 28 m/s 2 D) 48 m/s 2 E) 57 m/s 2 Ans: E Refer To: Ref 3-2 Difficulty: Hard SectionDef: Section 3-2 and Section 3-3 16. What was the magnitude of the displacement of the spaceship during the 25 seconds? A) 2.0 × 10 4 m B) 1.4 × 10 4 m C) 2.8 × 10 4 m D) 1.0 × 10 4 m E) 1.7 × 10 2 m Ans: A Refer To: Ref 3-2 Difficulty: Hard SectionDef: Section 3-2 and Section 3-3 17. A football is kicked at an angle q with respect to the horizontal. Which one of the following statements best describes the acceleration of the football during this event if air resistance is neglected? A) The acceleration is zero m/s 2 at all times. B) The acceleration is 9.8 m/s 2 at all times. C) The acceleration is zero m/s 2 when the football has reached the highest point in its trajectory. D) The acceleration is positive as the football rises, and it is negative as the football falls. E) The acceleration starts at 9.8 m/s 2 and drops to some constant lower value as the ball approaches the ground. Ans: B Difficulty: Easy SectionDef: Section 3-2 and Section 3-3

18. A baseball is hit upward and travels along a parabolic arc before it strikes the ground. Which one of the following statements is necessarily true? A) The acceleration of the ball decreases as the ball moves upward. B) The velocity of the ball is zero m/s when the ball is at the highest point in the arc. C) The acceleration of the ball is zero m/s 2 when the ball is at the highest point in the arc. D) The x -component of the velocity of the ball is the same throughout the ball's flight. E) The velocity of the ball is a maximum when the ball is at the highest point in the arc. Ans: D Difficulty: Medium SectionDef: Section 3-2 and Section 3-3 19. A physics student standing on the edge of a cliff throws a stone vertically downward with an initial speed of 10.0 m/s. The instant before the stone hits the ground below, it is traveling at a speed of 30.0 m/s. If the physics student were to throw the rock horizontally outward from the cliff instead, with the same initial speed of 10.0 m/s, what is the magnitude of the velocity of the stone just before it hits the ground? A) 10.0 m/s B) 20.0 m/s C) 30.0 m/s D) 40.0 m/s E) The height of the cliff must be specified to answer this question. Ans: C Difficulty: Hard SectionDef: Section 3-2 and Section 3-3 20. A tennis ball is thrown from ground level with velocity directed 30° above the horizontal. If it takes the ball 0.5 s to reach the top of its trajectory, what is the magnitude of the initial velocity? A) 4.9 m/s B) 9.8 m/s C) 11.3 m/s D) 19.6 m/s

Reference: Ref 3-4 A projectile fired from a gun has initial horizontal and vertical components of velocity equal to 30 m/s and 40 m/s, respectively. 23. Determine the initial speed of the projectile. A) 40 m/s B) 50 m/s C) 60 m/s D) 70 m/s E) 80 m/s Ans: B Refer To: Ref 3-4 Difficulty: Easy SectionDef: Section 3-2 and Section 3-3 24. At what angle is the projectile fired (measured with respect to the horizontal)? A) 37° B) 40° C) 45° D) 53° E) 60° Ans: D Refer To: Ref 3-4 Difficulty: Easy SectionDef: Section 3-2 and Section 3-3 25. Approximately how long does it take the projectile to reach the highest point in its trajectory? A) 1 s B) 2 s C) 4 s

D) 8 s E) 16 s Ans: C Refer To: Ref 3-4 Difficulty: Medium SectionDef: Section 3-2 and Section 3-3 26. What is the speed of the projectile when it is at the highest point in its trajectory? A) 0 m/s B) 20 m/s C) 30 m/s D) 40 m/s E) 50 m/s Ans: C Refer To: Ref 3-4 Difficulty: Medium SectionDef: Section 3-2 and Section 3-3 27. What is the acceleration of the projectile when it reaches its maximum height? A) zero m/s 2 B) 9.8 m/s 2 , downward C) 4.9 m/s 2 , downward D) less than 9.8 m/s 2 and non-zero. E) Its magnitude is 9.8 m/s 2 ; and its direction is changing. Ans: B Refer To: Ref 3-4 Difficulty: Easy SectionDef: Section 3-2 and Section 3-3 28. What is the magnitude of the projectile's velocity just before it strikes the ground? A) zero m/s

31. A spring-loaded gun is aimed horizontally and is used to launch identical balls with different initial speeds. The gun is at a fixed position above the floor. The balls are fired one at a time. If the speed of the second ball fired is twice the speed of the first ball fired, how is the horizontal range (denoted R in the figure) affected? A) The range for both balls will be the same. B) The range of the second ball will be half as much as that of the first ball. C) The range of the second ball will be twice as large as that of the first ball. D) The range of the second ball is about 1.4 times larger than that of the first ball. E) The range of the second ball will be smaller than that of the first ball by a factor of 1.4. Ans: C Difficulty: Medium SectionDef: Section 3-2 and Section 3-3 Reference: Ref 3-5 A shell is fired with a horizontal velocity in the positive x direction from the top of an 80-m high cliff. The shell strikes the ground 1330 m from the base of the cliff. The drawing is not to scale. 32. Determine the initial speed of the shell. A) 4.0 m/s B) 9.8 m/s C) 82 m/s D) 170 m/s E) 330 m/s Ans: E Refer To: Ref 3-5 Difficulty: Hard SectionDef: Section 3-2 and Section 3-3 33. What is the magnitude of the velocity of the shell as it hits the ground? A) 4.0 m/s

B) 9.8 m/s C) 82 m/s D) 170 m/s E) 330 m/s Ans: E Refer To: Ref 3-5 Difficulty: Medium SectionDef: Section 3-2 and Section 3-3 34. What is the magnitude of the acceleration of the shell just before it strikes the ground? A) 4.0 m/s 2 B) 9.8 m/s 2 C) 82 m/s 2 D) 170 m/s 2 E) 330 m/s 2 Ans: B Refer To: Ref 3-5 Difficulty: Easy SectionDef: Section 3-2 and Section 3-3 35. An arrow is shot horizontally from a height of 4.9 m above the ground. The initial speed of the arrow is 45 m/s. Neglecting friction, how long will it take the arrow to hit the ground? A) 9.2 s B) 6.0 s C) 1.0 s D) 1.4 s E) 4.6 s Ans: C Difficulty: Medium SectionDef: Section 3-2 and Section 3-3

Ans: A Difficulty: Hard SectionDef: Section 3-2 and Section 3-3 39. A bullet is aimed at a target on the wall a distance L away from the firing position. Because of gravity, the bullet strikes the wall a distance Δ y below the mark as suggested in the figure. N ote : The drawing is not to scale. If the distance L was half as large and the bullet had the same initial velocity, how would Δ y be affected? A) Δ y will double. B) Δ y will be half as large. C) Δ y will be four times larger. D) Δ y will be one fourth as large. E) Δ y is not possible to determine unless numerical values are given for the distances. Ans: D Difficulty: Easy SectionDef: Section 3-2 and Section 3-3 Reference: Ref 3-6 A tennis ball is thrown upward at an angle from point A . It follows a parabolic trajectory and hits the ground at point D . At the instant shown, the ball is at point B . Point C represents the highest position of the ball above the ground. 40. While in flight, how do the x and y components of the velocity vector of the ball compare at the points B and C ? A) The velocity components are non-zero at B and zero at C . B) The x components are the same; the y component at C is zero m/s. C) The x components are the same; the y component has a larger magnitude at C than at B . D) The x component is larger at C than at B; the y component at B points up while at C, it points downward. E) The x component is larger at B than at C ; the y component at B points down while at C , it

points upward. Ans: B Refer To: Ref 3-6 Difficulty: Medium SectionDef: Section 3-2 and Section 3-3 41. While in flight, how do the x and y components of the velocity vector of the ball compare at the points A and D ? A) The velocity components are non-zero at A and are zero m/s at D . B) The velocity components are the same in magnitude and direction at both points. C) The velocity components have the same magnitudes at both points, but their directions are reversed. D) The velocity components have the same magnitudes at both points, but the directions of the x components are reversed. E) The velocity components have the same magnitudes at both points, but the directions of the y components are reversed. Ans: E Refer To: Ref 3-6 Difficulty: Medium SectionDef: Section 3-2 and Section 3-3 42. Which statement is true concerning the ball when it is at C, the highest point in its trajectory? A) The ball's velocity and acceleration are both zero. B) The ball's velocity is perpendicular to its acceleration. C) The ball's velocity is not zero, but its acceleration is zero. D) The ball's velocity is zero, but its acceleration is not zero. E) The horizontal and vertical components of the ball's velocity are equal. Ans: B Refer To: Ref 3-6 Difficulty: Medium SectionDef: Section 3-2 and Section 3-3

Ans: D Refer To: Ref 3-7 Difficulty: Medium SectionDef: Section 3-2 and Section 3-3 46. How far does the football travel horizontally before it hits the ground? A) 18 m B) 25 m C) 36 m D) 48 m E) 72 m Ans: B Refer To: Ref 3-7 Difficulty: Medium SectionDef: Section 3-2 and Section 3-3 Reference: Ref 3-8 A rock is kicked horizontally at a speed of 15 m/s from the edge of a cliff. The rock strikes the ground 65 m from the foot of the cliff of height H as suggested in the figure, which is not drawn to scale. Neglect air resistance. 47. How long is the rock in the air? A) 1.0 s B) 1.2 s C) 4.0 s D) 5.5 s E) 11.2 s Ans: C Refer To: Ref 3-8 Difficulty: Easy SectionDef: Section 3-2 and Section 3-3

48. What is the approximate value of H , the height of the cliff? A) 27 m B) 54 m C) 78 m D) 150m E) 300 m Ans: C Refer To: Ref 3-8 Difficulty: Hard SectionDef: Section 3-2 and Section 3-3 Reference: Ref 3-9 A projectile is fired horizontally with an initial speed of 50.0 m/s. Neglect air resistance. 49. What is the magnitude of the displacement of the projectile 3.00 s after it is fired? A) 29.4 m B) 44.1 m C) 150 m D) 156 m E) 194 m Ans: D Refer To: Ref 3-9 Difficulty: Medium SectionDef: Section 3-2 and Section 3-3 50. What is the speed of the projectile 3.00 s after it is fired? A) 29.4 m/s B) 50.0 m/s C) 58.0 m/s D) 79.4 m/s E) 98.6 m/s Ans: C