Final Exam Fall 2012 STUDY GUIDE

Transcription

1 Final Exam Fall 2012 STUDY GUIDE 1. What is science? How is it different than technology? 2. What is the scientific method? 3. In science, what is a law? 4. What is a hypothesis? 5. What is a scientific theory? How is a scientific theory different from an everyday theory? 6. What is the test of truth in science? 7. What is a quantitative observation? How is it different from a qualitative observation? 8. What important change did Galileo introduce to science? 9. What is the difference between a scientific idea and one that isn t scientific? 10. A student wants to find out if a particular kind of plant grows better in the sun or in the shade. She has two identical plants. She places one plant in sand and sets the plant in the sunlight. She adds minerals and water to the sand, as shown here at the right: Which of the following conditions should she use for the second plant to determine the effect of light?

2 11. A group of students is making paper airplanes. They think that the kind of paper and the design of the airplane may affect how far each paper airplane flies. The students test first to see if the kind of paper affects how far the airplane flies. They make several airplanes out of different kinds of paper, using the same design. Why is it important that all the planes have the same design? 12. Students have a small steel ball and a large steel ball, and they have a short ramp and a tall ramp. The students want to find out if a ball s size affects how far it can roll. What is the independent variable in this experiment? What is the dependent variable? What will need to remain the same? 13. A swimming team wants to select one of three fabrics for their new swimsuits. Each fabric is made of a different material. The team decides to do the following experiment: They cut the same size pieces from each fabric and wet each piece with the same amount of water. They hang the pieces in the sunlight and they check every two minutes to see if any of the pieces are dry. What can the team find out about the different fabrics from doing just this experiment? 14. A swimming team wants to select one of three fabrics for their new swimsuits. Each fabric is made of a different material. The team decides to do the following experiment: They cut the same size pieces from each fabric and wet each piece with the same amount of water. They hang the pieces in the sunlight and they check every two minutes to see if any of the pieces are dry. A. What is the independent variable in this experiment? B. The dependent variable? C. What is staying the same? 15. A student wants to buy a new skateboard. He wants to find out if the size of the wheels affects how far he can coast on the skateboard. He also wants to find out if the type of material the board is made of affects how far he can coast on the skateboard. He decides to compare two skateboard models that are the same size but are made of different materials and have different size wheels. He pushes off as hard as he can and stands on the skateboard until the skateboard comes to a stop. He tries each skateboard 5 times to see how far he can go. He uses the same pavement and the same starting point for all the trials. He finds out that he can coast farther with Model 1. What can he conclude from this test? 16. What is inertia? 17. A girl pushes a cart to the right with a 10 N force. A boy pushes it to the right with a 2 N force. What is the net force on the cart? 18. What is tension force, where is it found, and in what direction does it act? 19. What is the net force on any object in equilibrium?

3 20. What is the difference between speed and velocity? 21. What is meant by the term, net force? 22. Why do objects have weight? On what two things does weight depend? 23. How do you move in front of a motion detector to make a line that slants upward? 24. What does the slope of a velocity v. time graph tell you? What does the slope of a position v. time graph tell you? 25. Sketch a position-time graph of two objects, where one object starts behind the other one. One object should be moving away from the detector at a constant speed, and the other object should not be moving. 26. Sketch a position-time graph of two objects, traveling at the same speed, where one object starts behind the other one. 27. Sketch a position-time graph for two objects that start at the same place. One travels away from the detector at a fast constant speed. The other travels away from the detector at a slower constant speed. 28. Sketch a position-time graph for two objects that shows one object holding still while the other moves away from the detector at a moderate constant speed. 29. Sketch a position-time graph for two objects. Object 1 moves away from the detector at a fast constant speed. Object 2 moves toward the detector at a slow constant speed. 30. Sketch a position-time graph for two objects that start at different places, and move away from the detector at the same constant speed. 31. Draw the forces acting on the object for each of the following situations: A. A book falling off a table. B. A skydiver falling through the sky. C. A soccer ball after it has been hit straight up into the air. D. A leaf floating to the ground. 32. Draw the forces acting on the book for each of the following situations: A. A book sliding across the table at a constant speed. B. A book sliding across the table at a constant acceleration. C. A book sliding across the table slowing to a stop. D. A book motionless on the table.

4 33. Draw the forces acting on the backpack for each of the following situations: A. A backpack falling off a table. B. A backpack being lifted off a table. C. A backpack being placed on a table. D. A backpack hanging over a student's shoulder. 34. Suppose you are in a car that is going around a curve. The speedometer reads a constant 30 mi/h. A. Is your speed changing? a. If so, how? B. Is your velocity changing? a. If so, how? 35. What must be true about the forces acting on an object when the object is in equilibrium? 36. A car is parked on a hill. In order to keep the car from rolling downhill, how big is the friction force compared to the force trying to make the car go downhill? 37. A 1 N force and a 3 N force act on an object in opposite directions. What is the net force on the object? 38. The acceleration produced by a net force on an object is proportional to the mass of the object. The acceleration produced by a net force is proportional to the size of the net force. The acceleration points in the direction as the net force What is true about the force or forces acting on an object that is in free fall? 40. About how fast will a ball be moving if it has dropped for 4 seconds in free fall? 41. A light ball and heavy ball the same size are dropped at the same time. In free fall, which ball hits the ground first? 42. A light ball and heavy ball the same size are dropped at the same time. In air, which ball hits the ground first? 43. What is the terminal velocity of an object? 44. A car is moving at a constant velocity to the right on a rough surface. Sketch all of the forces acting on the car. 45. Draw a set of marks that represents where the car will be every second for 5 seconds if it's traveling at a constant velocity.

5 46. How many forces are involved in an interaction? 47. Your friend says that action-reaction pairs of forces cancel each other out because they re equal and opposite. She s wrong, and how do you correct her? 48. Which pulls harder the Sun on Earth, or Earth on the Sun? 49. Sketch all of the forces acting on an apple as it rests in your hand. 50. You kick a soccer ball with 500 N of force. How much force is exerted by the soccer ball on your foot? 51. At the beginning of the movie, Men in Black, a giant luna moth smashes into the windshield of the truck carrying the alien. Which hit with more force: the moth against the windshield, or the windshield against the moth? 52. At the beginning of the movie, Men in Black, a giant luna moth smashes into the windshield of the truck carrying the alien. Which accelerated more as a result, the moth or the truck? 53. Gravity pulls downward on a book placed on a table. Why does the book remain at rest? 54. When a Great Dane is tied to a tree there are forces on the Great Dane, tree, and ground. What force must be the greatest to get the system to move? A. Great Dane s pull on the tree B. Great Dane s push against the ground C. tree's pull on the Great Dane 55. Which force is greater: a bat hitting the ball, or the ball hitting the bat? 56. Which force is larger at the tug-of-war: the seniors pulling against the freshmen, or the freshmen pulling against the seniors? 57. In an action-reaction pair, which force is larger: the action or the reaction? 58. A fat turtle and a skinny hare reach the finish line at the same speed. Which has more momentum? 59. When BOTH the force and time of contact are tripled (x3), what happens to the impulse? 60. A wrestler falls and must stop by hitting either the squishy mat or the hard concrete floor. Which will change his momentum more? Why? 61. A wrestler falls and must stop by hitting either the squishy mat or the hard concrete floor. Which will give him more impulse? Why? 62. A wrestler falls and must stop by hitting either the squishy mat or the hard concrete floor. Which will exert more force on him? Why? 63. A wrestler falls and must stop by hitting either the squishy mat or the hard concrete floor. Which will take more time?

6 64. Give an example of (a) an inelastic collision and (b) an elastic collision. 65. You re a skateboard expert. You swoop by and pick up your physics textbook to study as you relax. After you pick up the book, how fast are you moving compared to your speed before you picked up the book? 66. You re a skateboard expert. You swoop by and pick up your physics textbook to study as you relax. After you pick up the book, how much momentum do (you + book) have compared to just your momentum before you picked up the book? 67. Why do you feel less stopping force when falling into a net rather than a rigid surface? 68. Tony, Christopher and "Walnuts" each shoot their guns at three identical blocks of wood. Tony s bullet hits a block of wood that moves away slowly. Christopher s bullet hits a block of wood that moves away a little bit faster. Walnuts bullet hits a block of wood that moves away really fast. Which block of wood has the most momentum after being shot?