Name: Class: Date: Vector Pretest Multiple Choice Identify the choice that best completes the statement or answers the question.. A word meaning size often used to describe scalar quantities is: a. magma. b. magenta. c. vector. d. magnitude. 2. A measured quantity that is described by stating a size and a direction is called a: a. scalar. b. magnitude. c. vector. d. victim. 3. If a force vector acting in a northeast direction is resolved into its components, any vector acting in the north-south direction would be called a(n): a. hypotenuse. b. x-component. c. y-component. d. resultant. 4. Vector quantities include all of the following EXCEPT: a. velocity. b. force. c. speed. d. acceleration. 5. A scalar is a quantity that can be completely described using: a. direction only. b. magnitude only. c. both magnitude and direction. d. either magnitude or direction. 6. The diagram below represents a force acting at point P: The pair of forces that could represent x and y components of this force are: a. b. 2 c. 3 d. 4 7. Which of the following is a physical quantity that has a magnitude but no direction? a. vector c. resultant b. scalar d. frame of reference
Name: 8. Which of the following is a physical quantity that has both magnitude and direction? a. vector c. resultant b. scalar d. frame of reference 9. Which of the following is an example of a vector quantity? a. velocity c. volume b. temperature d. mass 0. Identify the following quantities as scalar or vector: the mass of an object, the number of leaves on a tree, wind velocity. a. vector, scalar, scalar c. scalar, vector, scalar b. scalar, scalar, vector d. vector, scalar, vector. Identify the following quantities as scalar or vector: the speed of a snail, the time it takes to run a mile, the free-fall acceleration. a. vector, scalar, scalar c. vector, scalar, vector b. scalar, scalar, vector d. scalar, vector, vector 2. In the figure above, which diagram represents the vector addition C = A + B? a. I c. III b. II d. IV 3. For the winter, a duck flies 0.0 m/s due south against a gust of wind with a speed of 2.5 m/s. What is the resultant velocity of the duck? a. 2.5 m/s south c. 7.5 m/s south b. 2.5 m/s south d. 7.5 m/s south 4. A car travels down a road at a certain velocity, v car. The driver slows down so that the car is traveling only half as fast as before. Which of the following is the correct expression for the resulting velocity? a. 2v car c. 2 v car b. 2 v car d. 2v car 5. A football player runs in one direction to catch a pass, then turns and runs twice as fast in the opposite direction toward the goal line. Which of the following is a correct expression for the original velocity and the resulting velocity? a. v player, 2v player c. v player, 2v player b. v player, 2v player d. 2v player, v player 2
Name: 6. A student walks from the door of the house to the end of the driveway and realizes that he missed the bus. The student runs back to the house, traveling three times as fast. Which of the following is the correct expression for the return velocity if the initial velocity is v student? a. 3v student c. b. 3 v student 3 v student d. 3v student 7. Which of the following is the best coordinate system to analyze a painter climbing a ladder at an angle of 60 to the ground? a. x-axis: horizontal along the ground; y-axis: along the ladder b. x-axis: along the ladder; y-axis: horizontal along the ground c. x-axis: horizontal along the ground; y-axis: up and down d. x-axis: along the ladder; y-axis: up and down 8. An ant on a picnic table travels 3.0 0 cm eastward, then 25 cm northward, and finally 5 cm westward. What is the magnitude of the ant s displacement relative to its original position? a. 70 cm c. 52 cm b. 57 cm d. 29 cm 9. In a coordinate system, a vector is oriented at angle θ with respect to the x-axis. The x component of the vector equals the vector s magnitude multiplied by which trigonometric function? a. cos θ c. sin θ b. cot θ d. tan θ 20. In a coordinate system, a vector is oriented at angle θ with respect to the x-axis. The y component of the vector equals the vector s magnitude multiplied by which trigonometric function? a. cos θ c. sin θ b. cot θ d. tan θ 2. How many displacement vectors shown in the figure above have horizontal components? a. 2 c. 4 b. 3 d. 5 3
Name: 22. How many displacement vectors shown in the figure above have components that lie along the y-axis and are pointed in the y direction? a. 0 c. 3 b. 2 d. 5 23. Which displacement vectors shown in the figure above have vertical components that are equal? a. d and d 2 c. d 2 and d 5 b. d and d 3 d. d 4 and d 5 24. Find the resultant of these two vectors: 2.00 0 2 units due east and 4.00 0 2 units 30.0 north of west. a. 300 units, 29.8 north of west c. 546 units, 59.3 north of west b. 58 units, 20. north of east d. 248 units, 53.9 north of west 4
Vector Pretest Answer Section MULTIPLE CHOICE. ANS: D PTS: DIF: basic REF: section 5. 2. ANS: C PTS: DIF: basic REF: section 5. 3. ANS: C PTS: DIF: basic REF: section 5. 4. ANS: C PTS: DIF: basic REF: section 5. 5. ANS: B PTS: DIF: basic REF: section 5. 6. ANS: B PTS: DIF: advanced REF: section 5. 7. ANS: B PTS: DIF: I OBJ: 3-. 8. ANS: A PTS: DIF: I OBJ: 3-. 9. ANS: A PTS: DIF: I OBJ: 3-. 0. ANS: B PTS: DIF: II OBJ: 3-.. ANS: B PTS: DIF: II OBJ: 3-. 2. ANS: B PTS: DIF: I OBJ: 3-.2 3. ANS: C Given v = 0.0 m/s south v 2 = 2.5 m/s north Solution v R = v v 2 = 0.0 m/s 2.5 m/s = 7.5 m/s v R = 7.5 m/s south PTS: DIF: IIIA OBJ: 3-.2 4. ANS: B PTS: DIF: II OBJ: 3-.3 5. ANS: C PTS: DIF: II OBJ: 3-.3 6. ANS: D PTS: DIF: II OBJ: 3-.3 7. ANS: C PTS: DIF: I OBJ: 3-2.
8. ANS: D Given x = 3.0 0 cm y = 25 cm x 2 = 5 cm Solution x tot = x + x 2 = (3.0 0 cm) + ( 5 cm) = 5 cm y tot = y = 25 cm d 2 = ( x tot ) 2 d = ( x tot ) 2 = (5 cm) 2 + (25 cm) 2 d = 29 cm PTS: DIF: IIIA OBJ: 3-2.2 9. ANS: A PTS: DIF: I OBJ: 3-2.3 20. ANS: C PTS: DIF: I OBJ: 3-2.3 2. ANS: C PTS: DIF: I OBJ: 3-2.3 22. ANS: B PTS: DIF: I OBJ: 3-2.3 23. ANS: B PTS: DIF: I OBJ: 3-2.3 2
24. ANS: D Given d = 2.00 0 2 units east d 2 = 4.00 0 2 units 30.0 north of west Solution Measuring direction with respect to x = (east), x = 2.00 0 2 units y = 0 x 2 = d 2 cos θ = (4.00 0 2 units)(cos 50.0 ) = 3.46 0 2 units y 2 = d 2 sinθ = (4.00 0 2 units)(sin 50.0 ) = 2.00 0 2 units x tot = x + x 2 = (2.00 0 2 units) + ( 3.46 0 2 units) =.46 0 2 units y tot = y + y 2 = 0 + (2.00 0 2 units) = 2.00 0 2 units d 2 = ( x tot ) 2 d = ( x tot ) 2 = (.46 0 2 units) 2 + (2.00 0 2 units) 2 d = 2.48 0 2 units Ê θ = tan Ë Á y tot x tot ˆ Ê = 2.00 0 2 ˆ units tan Ë Á.46 0 2 units = 53.9 d = 2.48 0 2 units, 53.9 north of west PTS: DIF: IIIB OBJ: 3-2.4 3