Semester Exam Study Guide- Answer Review

8th Grade

1. An object is in motion if its position changes relative to a ______ ______.Reference Point

2. What is the basic SI unit of length?Meter

3. When you know the speed and direction of an object’s motion, you know its ____.Velocity

4. What is negative accleration? Give an example?Slowing down- a car approaching a red light

5. A reference point is used for ______.Determining if something is moving.

6. Look at the graph on page 324. Does the graph show a negative acceleration?No

7. Page 324 graph: What does the line represent in terms of speed and acceleration?Speed increases; object accelerates.

8. Page 324 graph: What is the acceleration between 0 and 6 seconds?2m/s2

9. What units should be used when expressing acceleration?m/s2

10. Changing direction in one way that an object can _________.accelerate.

11. If an object moves in the same direction at a constant speed for 4 hours, what can you say about its velocity and acceleration?It did not change

12. Newton’s first law of motion is also called the law of _______.Inertia

13. Between a bowling ball, beach ball, tennis ball, and badminton birdie..which would have more inertia?A bowling ball.

14. The force that slows down the movement between objects is _________.Friction

15. Give an example of increasing friction intentionally.Throwing sand on an icy driveway

16. Balanced forces do not affect the motion of an object becauseThey are equal and opposite in direction.

17. What does the law of conservation of momentum state?Momentum cannot be lost, only transferred.

18. What is the difference between mass and weight?Weight- measures the gravitational pull by the earth on an

object.

19. A 200 kg cart is being accelerated by a tractor at a rate of 4 m/s2. How much force is the tractor putting on the cart?F = MAF = 200 X 4 = 800 N

20. Newton’s 3rd law says that for every action force there is a reaction force that ____ and ___.Equal and oppsite.

21. Which of Newton’s laws relates force, mass, and acceleration in the formula F= ma?2nd

22. One way to increase acceleration of an object is by _____ ____.Increasing Force

23. A 0.5 kg ball is rolled across the floor with a velocity of 2.5 m/s. What is the ball’s momentum?Momentum = mass X velocityMomentum = 0.5 kg X 2.5 m/s1.25 kg X m/s

24. Why is it possible to throw a 0.15 kg baseball much further than a 7kg bowling ball?The same force is applied to a lighter object.

25. A speedboat pulls a 60 kg water skier. The force causes the skier to accelerate at 1.5 m/s2. Calculate the net force that causes this acceleration.F = M X AF = 60 X 1.5F = 90

26. How do snowshoes enable a person to walk on deep snow?Increases the area over which the person’s

weight is distributed.

27. What happens to air pressure as elevation increases?It decreases

28. Water pressure increases as ____ ___.Depth increases

29. What scientific rule describes why water squirts from a plastic bottle when it is squeezed?Pascal’s

30. Which principle explains flight?Bernoulli’s

31. During high winds, the windows in a building may bulge outward because the air pressure inside the building is ___ ____ the air pressure outside the building.Greater Than

32. What scientific rule states that the buoyant force on an object is equal to the weight of the fluid displaced by the object?Archimedes

33. A pitcher is able to throw a curve ball partly because of ____ _____.Bernoulli’s Principle

34. Pascal’s principle states that when force is applied to a confined fluid, the change in pressure is transmitted _________.Equally to all parts of the fluid

35. What 2 factors does pressure depend on?Force & Area

36. What must happen for work to be done on an object?The object must move some distance as a result

of a force.

37. Give an example of work being done.Pushing a child on a swing

38. The mechanical advantage of a machine is the number of times a machine increases ________.The force exerted on the machine.

39. The mechanical advantage of a machine that changes only the direction of force is _____.1

40. The ideal mechanical advantage would equal the actual mechanical advantage if there were no loses due to _______.Friction

41. All machines have a(n) _____ of less than 100%Efficiency

42. The output work of a machine is 14,000J. If the input work is 17,500 J, the efficiency is _____.Efficiency = output / input X 100%Efficiency = 14,000J / 17,500 J80%

43. Frank does 2,800J of work in climbing a set of stairs. If he does the work in 3 seconds, what is his power output?Power = Work / TimePower = 2,800 J / 3 seconds= 933.3

44. How much work does an elephant do while moving a circus wagon 35 meters with a pulling force of 1,500 N.Work = Force X DistanceWork = 1,500 N X 35 Meters52,500

45. A machine makes work easier by multiplying force or __________, or by changing direction.Distance

46. The ability to do work is _____.Energy

47. Energy associated with motion is ____ _____.Kinetic energy

48. Kinetic energy increases as ___________.Both mass and velocity increase.

49. Give an example of an object that has kinetic energy?Rolling bowling ball

50. What does the law of conservation of energy state?No energy is created or destroyed

51. A change from one form of energy into another is a(n) ______ ______.Energy Transformation

52. Potential energy that depends on height is _____ ______ _____.Gravitational Potential Energy

53. What would always be true of an object possessing a kinetic energy of 0 joules?It is at rest

54. Which would always be true of an object possessing a potential energy of 0 joules?It is on the ground

55. If an object is at rest, it certainly does not possess this form of energy.Kinetic

56. A light bulb transforms _____ energy into ____ energy.Electrical to light

57. A ball thrown into the air has its greatest _____ energy as it reaches its highest point.Potential

58. As water runs over a waterfall, its ____ energy is transformed into ____ energy.Potential to kinetic

59. A baseball flying through the air has ____ energy because of its motion and ____ energy because of its position.Kinetic and potential

60. A large truck and a small car are moving at the same speed. The truck has greater kinetic energy because its _____ is greater.mass

61. How can moving water be used to produce electricity?Because most forms of energy can be changed

into other forms.

62. The rate at which energy is transferred is called _______.Power

63. Waves that move the particles of a medium parallel to direction the wave is traveling is ______ ______.Longitudinal waves

64. A disturbance that transfers energy from place to place is called _____.Wave

65. The distance between 2 corresponding parts of a wave is the _______.Wavelength

66. Electromagnetic waves can transfer energy without a(n) _____.Medium

67. Frequency is measured in ______.hertz

68. Which EM waves have the longest wavelengths and lowest frequencies?Radio waves

69. Red has the longest ______ of any color of visible light.Wavelength

70. The EM waves with the highest frequencies are called _____ ____.Gamma Rays

71. The _______ of a mechanical wave is a direct measure of its energy.amplitude

72. The _______ the wavelength a wave has, the ______ its frequency.Shorter; higher

73. What is a transverse wave?A disturbance that transfers energy perpendicular

to its medium

74. What is an example of a longitudinal wave?Sound

75. What is the low point on a transverse wave?Trough

76. If a person is generating a wave through a medium, what is the person transferring to that medium?Energy