Name ____________________ Mr. Willie Hastings Regents Physics Midterm Exam Review-2 Newton's Laws of Motion 1. Which body is in equilibrium? A) a satellite moving around Earth in a circular orbit B) a cart rolling down a frictionless incline 3. Which graph best represents the motion of an object that is not in equilibrium as it travels along a straight line? A) C) an apple falling freely toward the surface of Earth D) a block sliding at constant velocity across a tabletop B) 2. The data table below lists the mass and speed of four different objects. C) D) Which object has the greatest inertia? A) A B) B C) C D) D 4. Base your answer to the following question on Two forces are applied to a 2.0-kilogram block on a frictionless horizontal surface, as shown in the diagram below. The acceleration of the block is A) 5.0 m/s 2 to the right B) 5.0 m/s 2 to the left C) 3.0 m/s 2 to the right D) 3.0 m/s 2 to the left 5. Base your answer to the following question on In the graph below, the acceleration of an object is plotted against the unbalanced force on the object. 8. Base your answer to the following question on the diagram below which shows a 1-kilogram stone being dropped from rest from a bridge 100 meters above a gorge. What is the object's mass? A) 1 kg B) 2 kg C) 0.5 kg D) 0.2 kg 6. A force of F Newtons gives an object with a mass of M an acceleration of A. The same force F will give a second object with a mass of 2M an acceleration of A) A/2 B) 2A C) A What is the weight of the stone? A) .98 N B) 9.8 N C) 98 N D) 980 N D) A/4 7. An object weighing 4 Newtons rests on a horizontal tabletop. The force of the tabletop on the object is A) 0 N B) 4 N horizontally C) 4 N downward D) 4 N upward 9. At a given location on the earth's surface, which graph best represents the relationship between an object's mass (M) and weight (W) ? A) B) C) D) 10. A box decelerates as it moves to the right along a horizontal surface, as shown in the diagram at the right. Which vector best represents the force of friction on the box? A) B) C) D) 11. The diagram below shows a 4.0-kilogram object accelerating at 10. meters per second 2 on a rough horizontal surface. What is the magnitude of the frictional force Ff acting on the object? A) 5.0 N B) 10. N C) 20. N 12. Jill is pulling a 200. Newton sled through the snow at constant velocity using a horizontal force of 10. Newtons. What is the kinetic coefficient of friction of the sled on the snow? A) 0.02 B) 0.05 C) 0.20 D) 20 D) 40. N 13. According to your reference table, Approximate Coefficents of Friction, what is the minimum horizontal force needed to start a 300. N steel block on a steel table in motion? A) 0.57 N B) 074 N C) 171 N D) 222 N 14. The diagram below shows a child pulling a 50.-kilogram friend on a sled at a constant speed on a level surface by applying a 300.-newton force on the sled rope at an angle of 40.º with the horizontal. The force of friction between the sled and the surface is A) 510 N B) 230 N C) 190 N 15. Base your answer to the following question on The diagram below represents a block at rest on an incline. Which diagram best represents the forces acting on the block? (Ff = frictional force, FN = normal force, and Fw = weight.) A) B) C) D) D) 32 N Base your answers to questions 16 through 20 on the information below. 18. Determine the magnitude of the net force acting on the box. 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. 16. 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 . 19. Determine the mass of the box. 20. Calculate the magnitude of the acceleration of the box. [Show all work, including the equation and substitution with units.] 17. Calculate the magnitude of the frictional force acting on the box. [Show all work, including the equation and substitution with units.] Circular Motion/Gravitation/Hooke's Law 21. Base your answer to the following question on the information below. 23. The diagram below represents a ball undergoing uniform circular motion as it travels clockwise on a string. A 2.0 × 103-kilogram car travels at a constant speed of 12 meters per second around a circular curve of radius 30. meters. What is the magnitude of the centripetal acceleration of the car as it goes around the curve? A) 0.40 m/s 2 B) 4.8 m/s 2 C) 800 m/s 2 D) 9,600 m/s 2 22. Base your answer to the following question on the diagram below which represents a 2.0-kilogram mass moving in a circular path on the end of a string 0.50 meter long. The mass moves in a horizontal plane at a constant speed of 4.0 meters per second. At the moment shown in the diagram, what are the correct directions of both the velocity and centripetal acceleration of the ball? A) B) C) D) 24. Centripetal force Fc acts on a car going around a curve. If the speed of the car were twice as great, the magnitude of the centripetal force necessary to keep the car moving in the same path would be A) The speed of the mass is changed to 2.0 meters per second. Compared to the centripetal acceleration of the mass when moving at 4.0 meters per second, its centripetal acceleration when moving at 2.0 meters per second would be A) half as great B) twice as great C) one-fourth as great D) four times great B) C) D) 25. A 1750-kilogram car travels at a constant speed of 15.0 meters per second around a horizontal, circular track with a radius of 45.0 meters. The magnitude of the centripetal force acting on the car is A) 5.00 N B) 583 N C) 8750 N D) 3.94 × 10 5 N 26. Base your answer to the following question on the information and diagram below. A 4.0-kilogram model airplane travels in a horizontal circular path of radius 12 meters at a constant speed of 6.0 meters per second. 29. What is the acceleration due to gravity at a location where a 15.0-kilogram mass weighs 45.0 newtons? A) 675 m/s 2 B) 9.81 m/s 2 C) 3.00 m/s 2 D) 0.333 m/s 2 30. The weight of a 2.0-kilogram mass on planet A is 40 Newtons. The acceleration due to gravity on planet A is closest to At the position shown, what is the direction of the net force acting on the airplane? A) north B) south C) east D) west A) 20 m/s 2 B) 2.0 m/s 2 C) 80 m/s 2 D) 40 m/s 2 31. A student performed a laboratory investigation to determine the spring constant of a spring. The force applied to the spring was varied and the resulting elongation of the spring was measured. The student graphed the data collected, as shown below. 27. What is the magnitude of the gravitational force between two 5.0-kilogram masses separated by a distance of 5.0 meters? A) 5.0 × 10 0 N B) 3.3 × 10 –10 N C) 6.7 × 10 –11 N D) 1.3 × 10 –11 N According to the student’s graph, what is the spring constant for this spring? 28. Gravitational force exists between point objects and separated by distance . If the mass of is doubled and distance is tripled, what is the new gravitational force between and ? A) B) C) D) A) 0.050 m/N B) 9.8 N/kg C) 13 N• m D) 20. N/m 32. The spring in a scale in the produce department of a supermarket stretches 0.025 meter when a watermelon weighing 1.0 × 10 2 newtons is placed on the scale. The spring constant for this spring is A) 3.2 × 10 5 N/m B) 4.0 × 10 3 N/m C) 2.5 N/m D) 3.1 × 10 –2 N/m Base your answers to questions 33 through 35 on the information and digram below. A 1.50-kilogram cart travels in a horizontal circle of radius 2.40 meters at a constant speed of 4.00 meters per second. 33. Calculate the time required for the cart to make one complete revolution. [Show all work, including the equation and substitution with units.] 34. Describe a change that would quadruple the magnitude of the centripetal force. 35. On the blank circle above, draw an arrow to represent the direction of the acceleration of the cart in the position shown. Label the arrow a. Impulse-Momentum 36. Which object has the greatest momentum? A) a 12-kg mass moving at 1 m/sec B) a 5-kg mass moving at 2 m/sec C) a 9-kg mass moving at 3 m/sec D) a 4-kg mass moving at 4 m/sec 37. A 25-kilogram mass travels east with a constant velocity of 40. meters per second. The momentum of this mass is A) 1.0 × 10 3 kg-m/s east 39. A mother pushes her 120-newton child, who is sitting on a swing. If the mother exerts a 10.-newton force on the child for 0.50 second, what is the magnitude of the impulse imparted to the child by the mother? A) 5.0 N•s B) 20. N/s C) 60. N•s D) 240 N/s 40. Lab carts A and B are initially at rest with a compressed spring between them as shown in the diagram below. B) 9.8 × 10 3 kg-m/s east C) 1.0 × 10 3 kg-m/s west D) 9.8 × 10 3 kg-m/s west Which statement best describes the motion of the carts after the spring is released? 38. A 1.0-kilogram mass changes speed from 2.0 meters per second to 5.0 meters per second. The change in the object's momentum is A) 9.0 kg-m/sec B) 21 kg-m/sec C) 3.0 kg-m/sec D) 29 kg-m/sec A) Cart A has twice the momentum of cart B. B) Cart B has twice the momentum of cart A. C) Cart A has twice the velocity of cart B. D) Cart B has twice the velocity of cart A. Base your answers to questions 41 and 42 on the diagram below which represents carts A and B being pushed apart by a spring which exerts an average force of 50. Newtons for a period of 0.20 second. [Assume friction-less conditions.] 41. Compared to the magnitude of the impulse acting on cart A, the magnitude of the impulse acting on cart B is A) one-half as great B) twice as great C) the same D) four times as great 42. Compared to the total momentum of the carts before the spring is released, the total momentum of the carts after the spring is released is A) one-half as great B) twice as great C) the same D) four times as great 43. Base your answer to the following question on A 1.2-kilogram block and a 1.8-kilogram block are initially at rest on a frictionless, horizontal surface. When a compressed spring between the blocks is released, the 1.8-kilogram block moves to the right at 2.0 meters per second, as shown. What is the speed of the 1.2-kilogram block after the spring is released? A) 1.4 m/s B) 2.0 m/s C) 3.0 m/s D) 3.6 m/s 44. The diagram below shows a 4.0-kilogram cart moving to the right and a 6.0-kilogram cart moving to the left on a horizontal frictionless surface. When the two carts collide they lock together. (a) Determine the speed of the two carts after the collision. (Show all work including the equation and substitution with units) (b) What direction will the two locked carts be going after the collision? 45. A bicycle and its rider have a combined mass of 80. kilograms and a speed of 6.0 meters per second. What is the magnitude of the average force needed to bring the bicycle and its rider to a stop in 4.0 seconds? (Show all work including the equation and substitution with units) Answer Key Regents Midterm Practice 2 1. E 27. C 45. 2. D 28. A 3. B 29. C 4. C 30. A 5. C 31. D 6. A 32. B 7. D 33. v = d 8. B 9. A 10. D 11. B 12. B 13. D 14. B 15. D t t= 3.77 s 34. 16. 17. Examples: — double the speed of the car — reduce the radius to 0.60 m — quadruple the mass — double the mass of the cart and halve the radius — increase the speed of the cart to 5.66 m/s and double the mass of the cart — increase the speed of the cart to 5.66 m/s and halve the radius 35. 18. 2.0 N 19. 2.0 kg 20. 21. B 22. C 23. A 24. D 25. C 26. C 36. C 37. A 38. C 39. A 40. C 41. C 42. C 43. C 44. (a) 0.60 m/s (b) Left 1.2 × 10 2 N