Free Response- Exam Review

Transcription

1 Free Response- Exam Review Name Base your answers to questions 1 through 3 on the information and diagram below and on your knowledge of physics. A 150-newton force, applied to a wooden crate at an angle of 30. above the horizontal, causes the crate to travel at constant velocity across a horizontal wooden floor, as represented below. 1. Calculate the magnitude of the normal force exerted by the floor on the crate. [Show all work, including the equation and substitution with units.] 2. Determine the magnitude of the frictional force acting on the crate. 3. Calculate the magnitude of the horizontal component of the 150-newton force. [Show all work, including the equation and substitution with units.] Base your answers to questions 4 and 5 on the information and graph below and on your knowledge of physics. The graph below represents the speed of a marble rolling down a straight incline as a function of time. 4. Calculate the distance the marble travels during the first 3.0 seconds. [Show all work, including the equation and substitution with units.]

2 5. What quantity is represented by the slope of the graph? Base your answers to questions 6 and 7 on the information and diagram below and on your knowledge of physics. As represented in the diagram below, a constant 15-newton force, F, is applied to a 2.5-kilogram box, accelerating the box to the right at 2.0 meters per second squared across a rough horizontal surface. 6. Determine the magnitude of the force of friction on the box. 7. Calculate the magnitude of the net force acting on the box. [Show all work, including the equation and substitution with units.] Base your answers to questions 8 through 10 on the information below and on your knowledge of physics. A horizontal 20.-newton force is applied to a 5.0-kilogram box to push it across a rough, horizontal floor at a constant velocity of 3.0 meters per second to the right. 8. Calculate the coefficient of kinetic friction between the box and the floor. [Show all work, including the equation and substitution with units] 9. Calculate the weight of the box. [Show all work, including the equation and substitution with units.] 10. Determine the magnitude of the force of friction acting on the box.

3 Base your answers to questions 11 through 13 on the graph below, which represents the relationship between velocity and time for a car moving along a straight line, and your knowledge of physics. 11. Identify the physical quantity represented by the shaded area on the graph. 12. Determine the magnitude of the car s acceleration during the first 6.0 seconds. 13. Determine the magnitude of the average velocity of the car from t = 6.0 seconds to t = 10. seconds. 14. A 7.28-kilogram bowling ball traveling 8.50 meters per second east collides head-on with a 5.45 kilogram bowling ball traveling 10.0 meters per second west. Determine the magnitude of the total momentum of the two-ball system after the collision.

4 Base your answers to questions 15 and 16 on the information and graph below. The graph below shows the relationship between speed and elapsed time for a car moving in a straight line. 15. Calculate the total distance the car traveled during the time interval 4.0 seconds to 8.0 seconds. [Show all work, including the equation and substitution with units.] 16. Determine the magnitude of the acceleration of the car.

5 Base your answers to questions 17 through 19 on the information below. A river has a current flowing with a velocity of 2.0 meters per second due east. A boat is 75 meters from the north riverbank. It travels at 3.0 meters per second relative to the river and is headed due north. In the diagram below, the vector starting at point P represents the velocity of the boat relative to the river water. 17. Calculate or find graphically the magnitude of the resultant velocity of the boat. [Show all work, including the equation and substitution with units or construct the resultant velocity vector for the graph, using a scale of 1.0 centimeter = 0.50 meter per second. The value of the magnitude must be written below]

6 18. On the diagram below, use a ruler and protractor to construct a vector representing the velocity of the river current. Begin the vector at point P and use a scale of 1.0 centimeter = 0.50 meter per second. 19. Calculate the time required for the boat to cross the river. [Show all work, including the equation and substitution with units.] 20. Calculate the magnitude of the average gravitational force between Earth and the Moon. [Show all work, including the equation and substitution with units.] 21. Calculate the time required for a newton net force to stop a kilogram car initially traveling at 10. meters per second. [Show all work, including the equation and substitution with units.]

7 Base your answers to questions 22 through 25 on the information and diagram below. A model airplane heads due east at 1.50 meters per second, while the wind blows due north at 0.70 meter per second. The scaled diagram below represents these vector quantities. 22. Determine the angle between north and the resultant velocity. 23. Determine the magnitude of the resultant velocity. m/s 24. On the diagram, use a protractor and a ruler to construct a vector to represent the resultant velocity of the airplane. Label the vector R. 25. Using a ruler, determine the scale used in the vector diagram. 1.0 cm = m/s Base your answers to questions 26 through 28 on the information below. A student and the waxed skis he is wearing have a combined weight of 850 newtons. The skier travels down a snow-covered hill and then glides to the east across a snow-covered, horizontal surface. 26. Calculate the magnitude of the force of friction acting on the skis as the skier glides across the snow-covered, horizontal surface. [Show all work, including the equation and substitution with units. 27. Calculate the magnitude of the force of friction acting on the skis as the skier glides across the snow-covered, horizontal surface. [Show all work, including the equation and substitution with units.] 28. Determine the magnitude of the normal force exerted by the snow on the skis as the skier glides across the horizontal surface. N 29. A 0.50-kilogram frog is at rest on the bank surrounding a pond of water. As the frog leaps from the bank, the magnitude of the acceleration of the frog is 3.0 meters per second 2. Calculate the magnitude of the net force exerted on the frog as it leaps. [Show all work, including the equation and substitution with units.

8 Base your answers to questions 30 through 33 on the information below. An ice skater applies a horizontal force to a 20.-kilogram block on frictionless, level ice, causing the block to accelerate uniformly at 1.4 meters per second 2 to the right. After the skater stops pushing the block, it slides onto a region of ice that is covered with a thin layer of sand. The coefficient of kinetic friction between the block and the sand-covered ice is Calculate the magnitude of the force of friction acting on the block as it slides over the sand-covered ice. [Show all work, including the equation and substitution with units.] 31. Determine the magnitude of the normal force acting on the block. 32. On the diagram below, starting at point A, draw a vector to represent the force applied to the block by the skater. Begin the vector at point A and use a scale of 1.0 centimeters = 5.0 newtons. Base your answers to questions 35 through 37 on the information below. A kicked soccer ball has an initial velocity of 25 meters per second at an angle of 40º above the horizontal, level ground. [Neglect friction.] 35. On the diagram below, sketch the path of the ball s flight from its initial position at point P until it returns to level ground. 36. Calculate the maximum height the ball reaches above its initial position. [Show all work, including the equation and substitution with units.] 37. Calculate the magnitude of the vertical component of the ball s initial velocity [Show all work, including the equation and substitution with units.] 33. Calculate the magnitude of the force applied to the block by the skater [Show all work, including the equation and substitution with units.] 34. A person walks 150. meters due east and then walks 30. meters due west. The entire trip takes the person 10. minutes. Determine the magnitude and the direction of the person s total displacement.

9 Base your answers to questions 38 through 40 on the information and vector diagram below. A dog walks 8.0 meters due north and then 6.0 meters due east. 38. Determine the magnitude of the dog's total displacement. 39. On the diagram above, construct the resultant vector that represents the dog's total displacement. 40. Using a metric ruler and the vector diagram, determine the scale used in the diagram. 41. The graph below represents the velocity of an object traveling in a straight line as a function of time. Determine the magnitude of the total displacement of the object at the end of the first 6.0 seconds

10 Base your answers to questions 42 and 43 on the information below. A 747 jet, traveling at a velocity of 70. meters per second north, touches down on a runway. The jet slows to rest at the rate of 2.0 meters per second On the diagram below, point P represents the position of the jet on the runway. Beginning at point P, draw a vector to represent the magnitude and direction of the acceleration of the jet as it comes to rest. Use a scale of 1.0 centimeter = 0.50 meter/second Calculate the total distance the jet travels on the runway as it is brought to rest. [Show all work, including the equation and substitution with units.] 44. A 1500-kilogram car accelerates at 5.0 meters per second 2 on a level, dry, asphalt road. Determine the magnitude of the net horizontal force acting on the car. 45. Base your answer to the following question on the information below. A 75-kilogram athlete jogs 1.8 kilometers along a straight road in seconds. Determine the average speed of the athlete in meters per second.

11 Base your answers to questions 46 through 50 on the information below. A horizontal force of 8.0 newtons is used to pull a 20.-newton wooden box moving toward the right along a horizontal, wood surface, as shown. 46. Calculate the magnitude of the acceleration of the box. [Show all work, including the equation and substitution with units.] 47. Determine the mass of the box. 48. Determine the magnitude of the net force acting on the box. 49. Calculate the magnitude of the frictional force acting on the box. [Show all work, including the equation and substitution with units.] 50. Starting at point P on the diagram below, use a metric ruler and a scale of 1.0 cm = 4.0 N to draw a vector representing the normal force acting on the box. Label the vector FN. Base your answers to questions 51 and 52 on the information below. A force of 60. newtons is applied to a rope to pull a sled across a horizontal surface at a constant velocity. The rope is at an angle of 30. degrees above the horizontal. 51. Determine the magnitude of the frictional force acting on the sled.

12 52. Calculate the magnitude of the component of the 60.-newton force that is parallel to the horizontal surface. [Show all work, including the equation and substitution with units.] Base your answers to questions 53 through 56 on the information and diagram below. A spark timer is used to record the position of a lab cart accelerating uniformly from rest. Each 0.10 second, the timer marks a dot on a recording tape to indicate the position of the cart at that instant, as shown. 53. On the diagram below, mark at least four dots to indicate the position of a cart traveling at a constant velocity. 54. Calculate the average speed of the cart during the time interval t = 0 second to t = 0.30 second. [Show all work, including the equation and substitution with units.] 55. Calculate the magnitude of the acceleration of the cart during the time interval t = 0 second to t = 0.30 second. [Show all work, including the equation and substitution with units.] 56. Using a metric ruler, measure the distance the cart traveled during the interval t = 0 second to t = 0.30 second. Record your answer below, to the nearest tenth of a centimeter. cm Base your answers to questions 57 through 59 on the information and diagram below. Force A with a magnitude of 5.6 newtons and force B with a magnitude of 9.4 newtons act concurrently on point P. 57. Determine the magnitude of the resultant force.

13 58. On the diagram below, use a ruler and protractor to construct a vector representing the resultant of forces A and B. 59. Determine the scale used in the diagram. 1.0 cm = N Base your answers to questions 60 through 62 on the information below. A car on a straight road starts from rest and accelerates at 1.0 meter per second 2 for 10. seconds. Then the car continues to travel at constant speed for an additional 20. seconds. 60. Calculate the distance the car travels in the first 10. seconds. [Show all work, including the equation and substitution with units.] 61. On the grid provided, use a ruler or straightedge to construct a graph of the car's speed as a function of time for the entire 30.-second interval. 62. Determine the speed of the car at the end of the first 10. seconds. 63. A 10.-kilogram rubber block is pulled horizontally at constant velocity across a sheet of ice. Calculate the magnitude of the force of friction acting on the block. [Show all work, including the equation and substitution with units.] 64. Explain the difference between a scalar and vector quantity. 65. A skier on waxed skis is pulled at constant speed across level snow by a horizontal force of 39 newtons. Calculate the normal force exerted on the skier. [Show all work, including the equation and substitution with units.] 66. Objects in free fall near the surface of Earth accelerate downward at 9.81 meters per second 2. Explain why a feather does not accelerate at this rate when dropped near the surface of Earth.

14 Base your answers to questions 67 through 69 on the information and diagram below. A 10.-kilogram box, sliding to the right across a rough horizontal floor, accelerates at -2.0 meters per second due to the force of friction. Base your answers to questions 72 through 74 on the information and diagram below. In the scaled diagram, two forces, F1 and F2, act on a 4.0-kilogram block at point P. Force F1 has a magnitude of 12.0 newtons, and is directed toward the right. 67. Calculate the coefficient of kinetic friction between the box and the floor. [Show all work, including the equation and substitution with units.] 68. On the diagram provided, draw a vector representing the net force acting on the box. Begin the vector at point P and use a scale of 1.0 centimeter = 5.0 newtons. 69. Calculate the magnitude of the net force acting on the box. [Show all work, including the equation and substitution with units.] Base your answers to questions 70 and 71 on the information below. A car traveling at a speed of 13 meters per second accelerates uniformly to a speed of 25 meters per second in 5.0 seconds. 70. A truck traveling at a constant speed covers the same total distance as the car in the same 5.0-second time interval. Determine the speed of the truck. 71. Calculate the magnitude of the acceleration of the car during this -second time interval. [Show all work, including the equation and substitution with units.] 72. Calculate the magnitude of the acceleration of the block. 73. Determine the magnitude of the net force acting on the block. 74. Using a ruler and the scaled diagram, determine the magnitude of F2 in newtons. Base your answers to questions 75 and 76 on the information below. A physics class is to design an experiment to determine the acceleration of a student on inline skates coasting straight down a gentle incline. The incline has a constant slope. The students have tape measures, traffic cones, and stopwatches. 75. Indicate which equation(s) they should use to determine the student s acceleration. 76. Describe a procedure to obtain the measurements necessary for this experiment.

15 77. Two physics students have been selected by NASA to accompany astronauts on a future mission to the Moon. The students are to design and carryout a simple experiment to measure the acceleration due to gravity on the surface of the Moon. Describe an experiment that the students could conduct to measure the acceleration due to gravity on the Moon. Your description must include: the equipment needed what quantities would be measured using the equipment what procedure the students should follow inconducting their experiment what equations and/or calculations the students would need to do to arrive at a value for the acceleration due to gravity on the Moon 78. Base your answer to the following question on the information below. A soccer player accelerates a 0.50-kilogram soccer ball by kicking it with a net force of 5.0 newtons. Calculate the magnitude of the acceleration of the ball. [Show all work, including the equation and substitution with units.] 81. Base your answer to the following question on the information below. A force of 10. Newtons toward the right is exerted on a wooden crate initially moving to the right on a horizontal wooden floor. The crate weighs 25 Newtons. Base your answers to questions 79 and 80 on the information below. A hiker walks 5.00 kilometers due north and then 7.00 kilometers due east. 79. What total distance has she traveled? 80. What is the magnitude of her resultant displacement? a Calculate the magnitude of the force of friction between the crate and the floor. b On the diagram, draw and label all vertical forces acting on the crate. c On the diagram,draw and label all horizontal forces acting on the crate. d What is the magnitude of the net force acting on the crate? e Is the crate accelerating? Explain your answer.

16 Base your answers to questions 82 through 84 on the information and diagram below. A child is flying a kite, K. A student at point B, located 100. meters away from point A (directly underneath the kite), measures the angle of elevation of the kite from the ground as (Image of kite diagram not to scale) 82. A small lead sphere is dropped from the kite. Calculate the amount of time required for the sphere to fall to the ground. [Show all calculations, including the equation and substitution with units. Neglect air resistance.] 83. Use a metric ruler and your scale diagram to determine the height, AK, of the kite. 84. In the space provided above, use a metric ruler and protractor to draw a triangle representing the positions of the kite, K, and point A relative to point B that is given. Label points A and K. Use a scale of 1.0 centimeter = 10. meters. 85. Explain how to find the coefficient of kinetic friction between a wooden block of unknown mass and a tabletop in the laboratory. Include the following in your explanation: Measurements required Equipment needed Procedure Equation(s) needed to calculate the coefficient of friction

17 Base your answers to questions 86 through 88 on the information and diagram below. The following diagram is provided for practice purposes only. A 10.0-kilogram block slides at constant speed down a plane inclined at 20. to the horizontal, as shown. 86. In one or more complete sentences, describe the change in the motion of the block as the angle of inclination is increased to Determine the weight of the block. [Show all calculations, including the equation and substitution with units.] 88. On the diagram above, draw an arrow to represent and identify the direction of each of the three forces (weight, friction, normal force) acting on the block. Begin each arrow at point C and label each arrow with the force that it represents. 89. Jillian wishes to pull a 100. N copper box across a steel surface at a constant velocity. (Refer to your reference table, Approximate Coefficents of Friction.) a) Calculate the horizontal force she must apply. (Show all work) b) Originating from the dot in the center of the box above, construct a scaled vector showing Jillian's force and the frictional force. the forces must be drawn to a scale of 1.0 centimeter = 10. N. Be sure to label with numbers and units your vectors. c) If Jillian wished to make the box accelerate at 1.0 m/s 2, what force must she apply? (Show all work) 90. A box of mass m is held motionless on a frictionless inclined plane by a rope that is parallel to the surface of the plane. On the diagram above, draw and label all of the force vectors acting on the box.

18 Base your answers to questions 91 through 94 on the data table below, which describes the motion of an object moving in a straight line. 91. Based on your line of best-fit, what is the acceleration of the object? 92. On the same grid, sketch a line representing an object decelerating uniformly in a straight line. 93. Draw the line of best-fit. 94. Plot the data points. 95. The diagram below shows a 5.0-kilogram block accelerating at 6.0 meters per second 2 along a rough horizontal surface by the application of a horizontal force, F, of 50. Newtons. What is the magnitude in Newtons of the force of friction, Ff, acting on the block?

19 Base your answers to questions 96 through 99 on the information and diagram below, which is drawn to a scale of 1.0 centimeter = 30. meters. A student on building X is located 240. meters from the launch site B of a rocket on building Y. The rocket reaches its maximum altitude at point A. The student's eyes are level with the launch site on building Y. 96. Determine how much time is required for the rocket to fall freely from point A back to ground level. 97. What is the total distance the rocket must fall from its maximum altitude to reach the ground? 98. Determine the height, h, of the rocket above the student's eye level. 99. Using the scale diagram and a protractor, measure the angle of elevation, (theta), of the rocket and record it to the nearest degree.

20 Base your answers to questions 100 through 102 on the information and data table below. A car is traveling due north at 24.0 meters per second when the driver sees an obstruction on the highway. The data table below shows the velocity of the car at 1.0-second intervals as it is brought to rest on the straight, level highway Using your graph, determine the acceleration of the car. [Show all calculations, including the equation and substitution with units.] 101. Draw the best-fit line Using the information in the data table, construct a graph on the grid using the data points for velocity versus time. Base your answers to questions 103 through 107 on the information and vector diagram below Calculate the magnitude of the acceleration of the object. [Show all calculations, including the equation and substitution with units.]

21 104. What is the measure of the angle (in degrees) between east and the resultant force? 105. What is the magnitude of the resultant force? 106. On the vector diagram above, use a ruler and protractor to construct the vector that represents the resultant force Using a ruler, determine the scale used in the vector diagram above by finding the number of Newtons represented by each centimeter. Base your answers to questions 108 and 109 on the above picture and the information below. A 5.0-kilogram block weighing 49 Newtons sits on a frictionless, horizontal surface. A horizontal force of 20. Newtons toward the right is applied to the block. [Neglect air resistance.] 108. Calculate the magnitude of the acceleration of the block. [Show all calculations, including the equation and substitution with units.] 109. On the diagram above draw a vector to represent each of the three forces acting on the block. Use a ruler and a scale of 1.0 centimeter = 10. Newtons. Begin each vector at point C and label its magnitude in Newtons.

22 Base your answers to questions 110 through 113 on the information below and on your knowledge of physics. The diagram below represents a 4.0-newton force applied to a kilogram copper block sliding to the right on a horizontal steel table Describe what happens to the magnitude of the velocity of the block as the block slides across the table Determine the magnitude of the net force acting on the moving block Calculate the magnitude of the force of friction acting on the moving block. [Show all work, including the equation and substitution with units.] 113. Determine the weight of the block. Base your answers to questions 114 and 115 on the information below and on your knowledge of physics. A football is thrown at an angle of 30. above the horizontal. The magnitude of the horizontal component of the ball's initial velocity is 13.0 meters per second. The magnitude of the vertical component of the ball's initial velocity is 7.5 meters per second. [Neglect friction.] 114. The football is caught at the same height from which it is thrown. Calculate the total time the football was in the air. [Show all work, including the equation and substitution with units.]

23 115. On the axes above, draw a graph representing the relationship between the horizontal displacement of the football and the time the football is in the air.

24 Answer Key Free Response Exam Review m/s m./s N kg m/s or 7.3 kg m/s 15. d = 30. m m/s m/s c = 3.6 m/s or hypotenuse = 3.6 m/s or R = 3.6 m/s N or 196 N N m/s Equation and substitution with units. 34. a magnitude of 120m in a direction of east Acceleration or rate of change of velocity (speed). 6. Difference between 15 N and the student's response to the previous question. 19. t = 25 s 20. Fg = N 21. t = 2.0 s m/s m m/s m 0.4 m kg N Equation and substitution with units. 8. = 0.41 or Fg = 49 N N 11. displacement distance how far the car traveled cm = 0.20 m/s 0.04 m/s. 26. Ff = 40 N 27. Ff = µfn ; Ff = (0.05)(850 N); N cm = 2.0 m 0.2 m m N ± 0.4 N N 52. Ax= A cos Fx= (60 N)cos 30 Fx= 52 N cm ± 0.2 cm.

25 Answer Key Free Response Exam Review N 60. d = vit + ½at 2 d = 0 + ½(1.0 m/s 2 )(10. s) 2 d = 50. m or d = area = ½bh d = ½(10. s)( 10. m/s) d = 50. m 66. Examples: Air friction acts on the feather The feather is not in free fall m 91. Credit for indicating that the acceleration of the object is 1.2 m/s 2 or an answer that is consistent with the student's graph 92. Credit for drawing a decelerating straight line m/s 63. Ff = FN Ff = (.15)(10. kg)(9.81 m/s 2 ) Ff = 15 N or 14.7 N 64. Responses include, but are not limited to: A scalar quantity has magnitude only. A vector quantity has both magnitude and direction.; A vector quantity has direction.; A scalar quantity has no direction m/s a = 0.75 m/s N N ±0.6 N. 75. d = vit + at Examples: setting up a measured distance. measuring the time to travel that distance. 77. (essay) cm long A - B 85. (essay) 86. example: The block would accelerate or The speed of the block would not be constant. 87. w = mg w = (10.0 kg)(9.81 m/s 2 ) a) 36 N; b) drawing; c) 46 N Credit for plotting data correctly 95. Credit for 20. N or 20 N 96. t = at 2 ;t = 7 s m m m/s 2 south 101. The best fit line must be straight Graph 103. a = 4.5 m/s or a = 4.5 N/kg º N 106. diagram N or 5 Newtons 108. a = 4.0 m/s 2 or a = 4 N/kg 109. drawing km or 12. km or 12 km km or 8.6 km 110. The magnitude of the velocity increases. The block speeds up

26 Answer Key Free Response Exam Review N N or 2.0 N or 1.9 N

27 Answer Key Free Response Exam Review 77. freefall object, meterstick, stopwatch time of fall, distance of fall drop object from measured height, time its fall d = vit + at 2 pendulum string, mass, stopwatch, meterstick length of pendulum, period measure length of pendulum, period of pendulum T = 2 ( ) spring scale spring scale, known mass weight on Moon of known mass hang the weight on the spring scale and weigh it Fg(M) = mgm 85. The response must include: Measurements needed: normal force (weight or mass) of block, friction force Equipment needed: spring scale (and balance if mass of block is used) or computer force sensor Procedure: The procedure must include a means of finding the normal force and the force of friction, and a means of using them to determine the coefficient of friction, e.g., using the equation or finding the slope of a graph. Equation: Ff = µfn (and Fg = mg if mass is found first)