Name: Class: Date: ID: A F13--HPhys--Q4 Practice POST Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Which of the following is not an example of projectile motion? a. a long jumper in action b. a hot-air balloon drifting toward Earth c. a volleyball served over a net d. a baseball hit by a bat The figure above shows the path of a ball tossed from a building. Air resistance is ignored.. At what point of the ball s path shown in the figure above is the vertical component of the ball s velocity zero? a. C b. A c. D d. B 3. In the figure above, the horizontal component of the ball s velocity at A is a. equal to the vertical component of the ball s velocity at C. b. equal in magnitude but opposite in direction to the horizontal component of the ball s velocity at D. c. equal to the horizontal component of its initial velocity. d. zero. 4. In the figure above, at which point is the ball s speed about equal to the speed at which it was tossed? a. C b. D c. B d. A 5. In the figure above, the magnitude of the ball s velocity is greatest at location a. C. b. A. c. B. d. D. 6. In the figure above, the magnitude of the ball s velocity is least at location a. C. b. D. c. B. d. A. 7. Which of the following line segments on a velocity versus time graph is physically impossible? a. vertical line b. straight line with negative slope c. horizontal line d. straight line with positive slope 8. 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 b. vector, scalar, vector c. scalar, scalar, vector d. scalar, vector, scalar 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. tan θ b. cot θ c. sin θ d. cos θ 1
Name: ID: A 10. In the figure above, which diagram represents the vector subtraction C A B? a. III b. I c. IV d. II 11. In the figure above, which diagram represents the vector addition C A + B? a. IV b. III c. I d. II 1. Which of the following is a physical quantity that has both magnitude and direction? a. scalar b. resultant c. frame of reference d. vector 13. Suppose you are given a position versus time graph. The slope of a line drawn tangent to a point on the curve of this graph describes what quantity? a. position b. displacement c. acceleration d. instantaneous velocity 14. 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. 1 3 v student b. 1 3 v student c. 3v student d. 3v student 15. Which of the following units is the SI unit of velocity? a. meter b. meter second c. second per meter d. meter per second 16. Which displacement vectors shown in the figure above have vertical components that are equal? a. d 4 and d 5 b. d 1 and d c. d and d 5 d. d 1 and d 3 17. 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 b. 3 c. 5 d.
Name: ID: A 18. How many displacement vectors shown in the figure above have horizontal components? a. 5 b. 4 c. d. 3 19. Which of the following line segments on a position versus time graph is physically impossible? a. a vertical line b. a straight line that slopes to the left c. a straight line that slopes to the right d. a horizontal line 0. What is the SI unit of acceleration? a. m s b. m /s c. m/s d. m/s 1. For the winter, a duck flies 10.0 m/s due south against a gust of wind with a speed of.5 m/s. What is the resultant velocity of the duck? a. 7.5 m/s south b. 1.5 m/s south c. 1.5 m/s south d. 7.5 m/s south. 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 b. scalar, vector, vector c. scalar, scalar, vector d. vector, scalar, vector 3. Which of the following is an example of a vector quantity? a. volume b. mass c. temperature d. velocity 4. Acceleration is defined as a. the change in velocity. b. the rate of change of velocity. c. a rate of displacement. d. the rate of change of displacement. 5. The graph above describes the motion of a ball. At what point does the ball have an instantaneous velocity of zero? a. D b. B c. A d. C 6. The graph above describes the motion of a ball. At what point is the velocity of the ball equal to its velocity at B? a. D b. A c. C d. none of the above 7. What is the speed of an object at rest? a. 9.81 m/s b. 0.0 m/s c. 9.8 m/s d. 1.0 m/s 8. 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. tan θ b. cot θ c. cos θ d. sin θ 9. Which of the following is a physical quantity that has a magnitude but no direction? a. frame of reference b. resultant c. scalar d. vector 30. Which of the following is an example of projectile motion? a. a space shuttle being launched b. an aluminum can dropped straight down into the recycling bin c. a jet lifting off a runway d. a thrown baseball 3
Name: ID: A Problem 31. A rock is thrown straight upward with an initial velocity of 9.6 m/s in a location where the acceleration due to gravity has a magnitude of 9.81 m/s. To what height does it rise? 3. A firefighter 50.0 m away from a burning building directs a stream of water from a fire hose at an angle of 30.0 above the horizontal. If the velocity of the stream is 40.0 m/s, at what height will the stream of water strike the building? (a y g 9.81 m/s ) 33. A cat pushes a ball from a 10.00 m high window, giving it a horizontal velocity of 0.0 m/s. As it falls, the ball is deflected from the edge of a 3.00 m high downspout. The impact with the downspout has little effect on the ball s vertical motion. However, the ball s horizontal velocity increases by 0.05 m/s. How far from the base of the building does the ball land? (Assume no air resistance and that a y g 9.81 m/s.) 34. A rock is thrown downward from the top of a cliff with an initial speed of 1 m/s. If the rock hits the ground after.0 s, what is the height of the cliff? (Disregard air resistance. a g 9.81 m/s.) 35. A pebble falls vertically from the edge of a cliff 4 m high. After falling 1.0 s, the pebble glances a small rock protruding from the face of the cliff. The impact with ledge has negligible effect on the pebble s vertical motion. However, the pebble is deflected perpendicular to the face of the cliff with a horizontal velocity of 5 cm/s. How far from the base of the cliff does the pebble land? (Assume no air resistance and that a y g 9.81 m/s.) 36. A skateboarder rolls 5.0 m down a hill that descends at an angle of 0.0 with the horizontal. Find the horizontal and vertical components of the skateboarder s displacement. 37. Two cars pass each other traveling at the same speed. One car has a constant velocity of 15.0 m/s, east. The other car has a constant acceleration of 1.00 m/s, west. How much time will have elapsed until the cars are 164 m apart? 38. A shopping cart is given an initial velocity of.0 m/s and undergoes a constant acceleration of 3.0 m/s. What is the magnitude of the cart s displacement after the first 4.0 s of its motion? 39. A stone is thrown at an angle of 30.0 above the horizontal from the top edge of a cliff with an initial speed of 1 m/s. A stopwatch measures the stone s trajectory time from the top of the cliff to the bottom at 5.60 s. What is the height of the cliff? (Assume no air resistance and that a y g 9.81 m/s.) 40. A skater glides off a frozen pond onto a patch of ground at a speed of 1.8 m/s. Here she is slowed at a constant rate of 3.00 m/s. How fast is the skater moving when she has slid 0.37 m across the ground? 4
F13--HPhys--Q4 Practice POST Answer Section MULTIPLE CHOICE 1. ANS: B PTS: 1 DIF: I OBJ: 3-3.1. ANS: D PTS: 1 DIF: I OBJ: 3-3. 3. ANS: C PTS: 1 DIF: II OBJ: 3-3. 4. ANS: A PTS: 1 DIF: II OBJ: 3-3. 5. ANS: D PTS: 1 DIF: II OBJ: 3-3. 6. ANS: C PTS: 1 DIF: II OBJ: 3-3. 7. ANS: A PTS: 1 DIF: II OBJ: -. 8. ANS: C PTS: 1 DIF: II OBJ: 3-1.1 9. ANS: D PTS: 1 DIF: I OBJ: 3-.3 10. ANS: C PTS: 1 DIF: I OBJ: 3-1. 11. ANS: D PTS: 1 DIF: I OBJ: 3-1. 1. ANS: D PTS: 1 DIF: I OBJ: 3-1.1 13. ANS: D PTS: 1 DIF: I OBJ: -1.3 14. ANS: C PTS: 1 DIF: II OBJ: 3-1.3 15. ANS: D PTS: 1 DIF: I OBJ: -1.1 16. ANS: D PTS: 1 DIF: I OBJ: 3-.3 17. ANS: D PTS: 1 DIF: I OBJ: 3-.3 18. ANS: B PTS: 1 DIF: I OBJ: 3-.3 19. ANS: A PTS: 1 DIF: II OBJ: -1.3 0. ANS: C PTS: 1 DIF: I OBJ: -.1 1. ANS: A v 1 10.0 m/s south v.5 m/s north v R v 1 v 10.0 m/s.5 m/s 7.5 m/s v R 7.5 m/s south PTS: 1 DIF: IIIA OBJ: 3-1.. ANS: C PTS: 1 DIF: II OBJ: 3-1.1 3. ANS: D PTS: 1 DIF: I OBJ: 3-1.1 4. ANS: B PTS: 1 DIF: I OBJ: -.1 5. ANS: D PTS: 1 DIF: I OBJ: -. 6. ANS: D PTS: 1 DIF: II OBJ: -. 7. ANS: B PTS: 1 DIF: I OBJ: -1.1 8. ANS: D PTS: 1 DIF: I OBJ: 3-.3 9. ANS: C PTS: 1 DIF: I OBJ: 3-1.1 30. ANS: D PTS: 1 DIF: I OBJ: 3-3.1 1
PROBLEM 31. ANS: 4.7 m a g 9.81 m/s 9.6 m/s v f 0.0 m/s v f + a x x v f a (0.0 m/s) (9.6 m/s) ()( 9.81 m/s ) 4.7 m PTS: 1 DIF: IIIB OBJ: -3. 3. ANS: 18.7 m 40.0 m/s θ 30.0 x 50.0 m,y sin θ (40.0 m/s)(sin 30.0 ) 0.0 m/s,x cos θ (40.0 m/s)(cos 30.0 ) 34.6 m/s v x,x x v x t t x v x 50.0 m 34.6 m/s 1.45 s y,y t + 1 a y ( t) y (0.0 m/s)(1.45 s) + 1 ( 9. 81 m/s )(1.45 s) y 9.0 m 10.3 m y 18.7 m PTS: 1 DIF: IIIC OBJ: 3-3.3
33. ANS: 0.30 m y 1 10.00 m v x 0.0 m/s y 3.00 m v x 0.05 m/s x v x t 1 + v x t t t 1 t 1 y 1 1 a y ( t 1 ) t 1 y a y ( 10.00 m) ( 9.81 m/s ) 1.43 s ( y 1 y ) 1 a y ( t 1 ) t 1 ( y 1 y ) a y [( 10.00 m) ( 3. 00 m)] ( 9.81 m/s ) 1.19 s t t 1 t 1 1.43 s 1.19 s 0.4 s x v x t 1 + v x t (0.0 m/s)(1.43 s) + (0.05 m/s)(0.4 s) 0.30 m PTS: 1 DIF: IIIC OBJ: 3-3.3 34. ANS: 44 m a g 9.81 m/s t.0 s 1 m/s x t + 1 a( t) x ( 1 m/s)(.0 s) + 1 ( 9.81 m/s )(. 0 s) 44 m height of cliff 44 m PTS: 1 DIF: IIIA OBJ: -3. 3
35. ANS: 6 cm y 4 m v x 5 cm/s x v x t t t 1 1.0 s y 1 a y ( t 1 ) t 1 y a y ( 4 m) ( 9.81 m/s ). s t. s 1.0 s 1. s x v x t (5 cm/s)(1. s) 6 cm PTS: 1 DIF: IIIC OBJ: 3-3.3 36. ANS: d x 3.5 m; d y 8.55 m d 5.0 m, θ 0.0 d x d cos θ (5.0 m)(cos 0.0 ) 3.5 m d y d sin θ (5.0 m)(sin 0.0 ) 8.55 m PTS: 1 DIF: IIIB OBJ: 3-.3 4
37. ANS: 5.0 s,1, 15.0 m/s a 1.00 m/s d 164 m d d 1 + d,1 t +, t + 1 a ( t),1, v d v t + 1 a ( t) 0 1 a ( t) + v t d t Ê ( v) ± (v) 4 a ˆ Ë Á ( d) Ê a ˆ ( ) Ë Á Ê ˆ ()(15.0 m/s) ± [()(15.0 m/s)] 1.00 m/s 4 Ë Á ( 164 m) t Ê 1.00 m/s ˆ ( ) Ë Á t 30.0 s ± 35.0 s 5.0 s PTS: 1 DIF: IIIC OBJ: -.3 5
38. ANS: 3 m.0 m/s a 3.0 m/s t 4.0 s x t + 1 a( t) x (.0 m/s)(4.0 s) + 1 (3.0 m/s )(4.0 s) 8.0 m + 4 m x 3 m PTS: 1 DIF: IIIA OBJ: -.3 39. ANS: 10 m 1 m/s at 30.0 above the horizontal t 5.60 s g 9.81 m/s,y sin θ (1 m/s)(sin 30.0 ) 6.0 m/s y,y t + 1 a y ( t) (6.0 m/s)(5.60 s) + 1 ( 9. 81 m/s )(5.60 s) y 34 m 154 m 10 m h 10 m PTS: 1 DIF: IIIB OBJ: 3-3.3 40. ANS: 1.0 m/s 1.8 m/s a 3.00 m/s x 0.37 m v f + a x v f + a x (1.8 m/s) + ( 3.00 m/s )(0.37 m) v f 3. m /s. m /s 1.0 m /s v f 1.0 m/s PTS: 1 DIF: IIIA OBJ: -.3 6