Integrated Science Force Test

Transcription

1 Integrated Science Force Test Name: Answer Key For multiple-choice, please circle the correct letter. For short answer, be sure to use complete sentences and lots of details. To get full credit, you must show your work on any problems that require calculations! 1. What is the definition of magnitude? (1 pt) a) A force that opposes the motion of objects that touch as they move past each other. b) Containing terms of which an increase in one results in a decrease in the other. c) The overall force acting on an object after all the forces are combined. d) Size, extent, dimensions. 2. What is the definition of inverse? (1 pt) a) Containing terms of which an increase in one results in a decrease in the other. b) The result of a force distributed over an area. c) Containing terms of which an increase in one results in a greater increase in the other. d) A lack or shortage; a loss. 3. What is the definition of velocity? (1 pt) a) The amount of space taken up by an object. b) An attractive force that acts between any two masses. c) Speed in a given direction. It is a vector quantity. d) The difference in position between a final position and an initial position. 4. What is the definition of pressure? (1 pt) a) A push or a pull that acts on an object. b) The result of a force distributed over an area. c) The force of gravity acting on an object. d) The constant velocity of a falling object when the force of air resistance equals the force of gravity. 5. What keeps particles in a nucleus together? (1 pt) a) Strong nuclear force b) Repulsion c) Electrical force d) Gravitational force 6. This is the weakest force but it acts over an infinite distance. (1 pt) a) Magnetic b) Gravitational c) Strong nuclear d) Electromagnetic 7. Which force allows for nuclear fusion in a star? (1 pt) a) Magnetic b) Weak nuclear c) Strong nuclear d) Electromagnetic

2 8. This is the force that is responsible for light. (1 pt) a) Magnetic b) Weak nuclear c) Strong nuclear d) Electromagnetic 9. Why does strong nuclear force need to be the strongest force? (1 pt) a) Because otherwise gravitational force would cause the planets to stick together. b) Because otherwise weak nuclear force would cause all the electrons to be emitted. c) Because otherwise the electromagnetic force would cause the nucleus to fly apart. d) Because otherwise magnetism would not exist. 10. The moon s gravity is only one sixth that of Earth s. Explain how the weight and mass of an object differ between the two locations. (2 pts) Mass would be the same in the two locations. Weight would be less on the moon because it has less gravitational pull. 11. Which of the following two examples would have more gravitational force? (1 pt) a) 5 km 2,000 kg 2,000 kg b) 5 km 5,000 kg 5,000 kg c) They would have the same gravitational force. d) It is impossible to tell. 12. Which of the following two examples would have more gravitational force? (1 pt) a) 10 km 2,000 kg 2,000 kg b) 5 km 2,000 kg 2,000 kg c) They would have the same gravitational force. d) It is impossible to tell.

3 13. The SI unit of pressure is the (1 pt) a) Newton b) Pascal c) psi d) Joule 14. Increasing which variable would decrease the pressure of a contained gas? (1 pt) a) Temperature b) Volume c) Mass d) Joules 15. As the temperature of a gas increases, its kinetic energy (1 pt) a) Increases b) Decreases c) Stays the same d) Depends on the type of gas 16. Fill out the following table based on the combined gas law. (2 pts) Gas Pressure 1 (atm) Volume 1 (L) Temperature 1 (K) Pressure 2 (atm) Volume 2 (L) Temperature 2 (K) A B C D In Earth s atmosphere, pressure and temperature both decrease as altitude increases. Weather balloons expand as they rise. Which has more effect on the weather balloon, the decrease in pressure or the decrease in temperature? Explain your answer. (2 pts) As temperature decreases, volume should decrease. However, as pressure decreases, volume should increase. Therefore, the decrease in pressure has a greater affect because the volume increases.

4 Pressure (atm) 18. Using the following table, graph the relationship between volume and pressure. Pressure is considered the dependent variable. Remember to label your axis! (4 pts) Volume (m 3 ) Pressure (atm) Boyle's Law Volume (m 3 )

5 Volume (L) Use the graph below to answer questions 19 and Gas Characteristics Gas A Gas B Gas C Temperature (deg C) 19. Which of the following statements is true? (1 pt) a) Gas A had the greatest increase in volume. b) Gas B had the greatest increase in volume. c) Gas C has the greatest increase in volume. d) All the gases had the same increase in volume. 20. Approximately what temperature is gas B when it has a volume of 40 L? 190 ⁰C (1 pt) 21. What is an electromagnet? (1 pt) An electromagnet is a type of magnet that is produced by the flow of an electric current. 22. Give two examples of where you might find an electromagnet in your home. (2 pts) Doorbell, washer, dryer, refrigerator, speakers 23. What makes an electromagnet useful? (1 pt) a) It has a north and a south pole. b) It can be turned on and off. c) It can measure whether something is metal or not. d) It does not need a source of power.

6 24. Which change occurs in an electric generator? (1 pt) a) Electrical energy to mechanical energy. b) Thermal energy to wind energy. c) Mechanical energy to electrical energy. d) Nuclear energy to thermal energy. 25. Which change occurs in an electric motor? (1 pt) a) Electrical energy to mechanical energy. b) Thermal energy to wind energy. c) Mechanical energy to electrical energy. d) Nuclear energy to thermal energy. 26. Two generators are identical except for the loops of wire that rotate through their magnetic fields. One has twice as many turns of wire as the other one does. Which generator would produce the most electric current? Why? (2 pts) The generator with twice as many coils would produce the most electricity because the amount of electricity generated increases as the number of coils increases. Use the diagram below to answer the following two questions. The diagram below shows a model of a simple electrical generator. There are conducting pieces that allow the circuit to remain closed as the handle is turned. The bulb can be lit as current electricity is produced in the wires when the handle turns the metal coil. 27. What do the pieces labeled X represent? (1 pt) The pieces labeled X represent the permanent magnet. 28. Describe how an electrical current is produced when the coil is turned. (2 pts) When the coil is turned, the magnets cause movement in the electrons within the coil. The movement of electrons causes an electric current.

7 Use the diagram below to answer questions 29 and 30. E A B D C 29. If A = 60 N, B = 20 N, C = 30 N, D = 30 N, and E = 30 N, what is the net force on the object? (1 pts) The net force on the object is 50 N to the right. 30. If all of the other forces remain the same, what does the force of D need to be for the net force to be zero? (1 pt) The force of D needs to be 80N. 31. Use a vector diagram to show the result of a force that is 20 N to the east and a force that is 10 N to the north. Be sure to list your scale! (3 pts) 10 N N 20 N Scale: 1 box = 5 N Resultant force vector: 22.4 N to the northeast 32. Convert 3800 g/cm 3 to kg/cm 3. (2 pts)

8 I can walk 10 miles in 250 minutes. What is my speed in m/s? Round to nearest tenth. (2 pts) 33. What is the purpose of an experiment? (1 pt) a) To communicate data b) To test a hypothesis c) To prove a scientific law d) None of the above 35. When the ratio of two variables is constant, their relationship can be described as (1 pt) a) Inversely proportional b) Interdependent c) Linear d) Parallel 36. In a controlled experiment, (1 pt) a) There are multiple responding variables b) The responding variable is kept constant c) The manipulated variable is kept constant. d) Only one variable at a time is deliberately changed. 37. In an experiment, what is the difference between the results and the conclusions? (1 pt) The results summarize the observations. The conclusions connect the results back to the hypothesis. Conversion Factors: 100 cm = 1 m 1 mile = 1.61 km

9 Cost ($) Challenge questions (Extra credit 1% each. You must show your work!) 1. Carpet is on sale at Store A for $25/yd 2 with an installation cost of $100. The same carpet is on sale at Store B for $3.00/ft 2 with an installation cost of $50. Graph the relationship between cost and area of the room for the two carpets. Based on the graph, at what area do the carpets cost the same amount? Calculate the cost for each carpet at that area to verify your answer Area (ft 2 ) Store A Store B The carpets will cost the same at ~230 ft 2. Cost at Store A = $2.78/ft 2 x 230 ft 2 + $100 = $ Cost at Store B = $3.00/ft 2 x 230 ft 2 + $50=$740.00

10 2. How would you make the gravitation force of the second objects equal the gravitational force of the first objects without changing the objects themselves? I want a quantitative answer not a qualitative one. 1 st objects: 5 km 2,000 kg 5,000 kg 2 nd objects: 5 km 25,000 kg 30,000 kg G=(mass 1) times (mass 2) divided by the distance squared. G 1 =(2,000 x 5,000)/5 2 = 400,000 G 2 =(25,000 x 30,000)/d 2 =400,000 so d 2 =(25,000 x 30,000)/400,000=1,875 so d=43.3 Move the second objects 43.3 km apart to make the force of gravity equal. 3. I am hiking and get lost. First I hike 5 miles north. Then I hike 2 miles east. Then I hike 2.8 miles directly northwest. Then I hike another 7.1 miles directly southwest. Finally, I hike 3 miles north. Where am I compared to where I started? You must compute this mathematically! You must provide a scale and a compass rose. Scale: 1 box = 1 mile, Resultant vector: = = = 7.1 miles northwest N

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