Untitled Flashcards Set

1. “Physics” could best be described as the study of

the general principles underlying natural phenomena.

2. Regarding the validity of Ptolemy’s and Copernicus’ theories:

they were both good theories, but Copernicus’ point of view ultimately turned out to be more useful.

3. At the microscopic level, the difference between liquids and solids is that

the liquid’s atoms move throughout the liquid, while the solid’s atoms remain near their original locations.

4. A block of granite is actually mostly empty space because the atoms making up the granite are

themselves mostly empty space.

5. A book is given a brief shove along a table top and released so that it slides a short distance and comes to rest. According to Aristotle, it stopped because

its natural motion is to come to rest.

6. A book is given a brief shove along a table top and released so that it slides a short distance and comes to rest. Galileo would say that the book stopped because

of friction.

7. In what kind of path would the planets move if no force acted on them?

Straight line with no acceleration.

8. An auto is moving at a steady 50 mph up a long straight [constant “slope”] incline. While it is on this incline

its acceleration is zero but its velocity is not zero.

9. A car is rounding the top, or crest, of a hill while moving at a steady 50 km/hr. What can you say about this car’s acceleration, and why?

The car is accelerated, because its direction of motion is changing.

10. After an object is released and it starts to fall, in twice the time, it will attain a speed that is

twice as fast.

11. The main point of Newton’s law of motion is that forces cause

acceleration.

12. You throw a ball straight upward. While it is moving upward, the net force on the ball is

in the downward direction.

13. Max pushes against a brick wall with a force of 10 newtons for a time of 5 seconds. How much work does Max do on the wall?

none.

14. Would you be richer if you had a hunk of gold whose weight is 1 newton on the moon, or one whose weight is 1 newton on Earth, and why?

1 newton on the moon, because then the gold’s mass would be larger.

15. Suppose that you stand, motionless, on the floor. Regarding the force by the floor on your feet

there is an upward force by the floor on your feet, even though you are not accelerating.

16. A book rests on a table, and the table rests on the ground. Which of the following pairs of forces forms a force pair, or action-reaction pair, obeying Newton’s law of force pairs?

The table pushing up on the book and the book pushing down on the table.

17. An auto moves at a steady 50 mph down a straight level road. Which of the following is the forward drive force on the auto?

The forward push by the road on the tires.

18. As the moon circles Earth, the net force on it is

directed inward toward Earth.

19. What similarity did Isaac Newton perceive between a falling apple and the moon?

Both have forces on them toward Earth’s center, and accelerations directed toward Earth’s center.

20. Astronauts in orbit around Earth feel weightless because

they are in “free fall” around Earth.

21. Compared to the gravitational force on a 1 kg object, the gravitational force on a 2 kg object is:

twice as large.

22. Which of the following would increase the gravitational force between two objects?

Moving the two objects closer together.

23. Today, we know that Newton’s “laws” are:

often incorrect when applied to molecular-sized objects.

24. Under what condition can a force act on an object and yet do no work on that object?

If the object does not move.

25. How much work do you do when you lift a 3 N apple by 2 m during a time of 6 s?

6 J

26. One situation in which the law of conservation of energy is violated is:

Nonsense–no violations of this law have ever been observed.

27. The rate of doing work, or of transforming energy, can be measured in:

watts.

28. You push your physics book across your desk, leaving the book at rest on the desk at the end of the process. Which of the following best represents the overall energy conversion during this process?

chemical → thermal.

29. What energy transformation occurs during photosynthesis?

radiant energy → chemical energy.

30. Evidence that things are made of atoms comes from:

Brownian motion.

31. Light waves are:

traveling disturbances in an electromagnetic field.

32. Which of the following best represents the energy transformations in a coal-fired electric power plant?

chemical → thermal → kinetic → electromagnetic.

33. Two different isotopes of the same element have:

the same chemical properties, but different properties in nuclear processes.

34. One phenomenon or experiment that supports the wave theory of matter is:

the double-slit experiment with electrons.

35. According to the theory of relativity, is everything relative?

No, lightspeed is not relative.

36. Why might excess CO2 in the atmosphere heat up the earth?

Because CO2 absorbs, or traps, infra-red radiation.

37. Which of the following is true?

Electric field lines point in towards negative charges.

38. Samuel and Samantha are twins, born at the same time on Earth. Samantha is taken on a long trip into outer space, at a speed close to lightspeed, and returns to Earth. When she returns:

Samuel and Samantha both observe that Samuel is older than Samantha.

39. According to Einstein’s general theory of relativity, the apparent gravitational “force” exerted by one object on another actually results from:

the warping of space-time created by the first object, which then modifies the trajectory of the second object.

40. Which one of the following is responsible for the “one-way” nature of time, i.e. for the distinction between past and future?

the second law of thermodynamics.

41. The three main types of radiation produced by the sun are:

infra-red, visible, and ultra-violet.

42. The “efficiency” of a heat engine is defined to be:

work output divided by thermal energy input.

43. All magnetic forces are produced by:

charges in motion.

44. According to the principle of equivalence, gravity is equivalent to:

acceleration.

45. Different colors correspond to electromagnetic waves of different:

frequencies.

46. The forces that hold the nucleus together are:

All of the above.

47. Christian sends a laser beam toward Sonja. As the tip of the beam passes her rocket, Sonja observes that:

the laser beam moves past her at 300,000 km/s.

48. A system’s “entropy” is:

the amount of microscopic disorganization in the system.

49. Since matter is made of electrically charged particles, why don’t we feel electric forces all the time?

Because ordinary matter contains as many electrons as protons, leading to no net macroscopic effect.

50. How does a radio station transmit a radio signal to your ear?

Electrons moving in the station’s antenna send out an electromagnetic wave that travels to your radio, where the wave is transformed into a sound wave that travels to your ear.

51. When you touch a piece of ice:

thermal energy flows from your hand to the ice.

52. Ernest Rutherford’s experiments demonstrated that:

the atom contains a tiny nucleus containing most of the atom’s mass.

53. Conventional automobile efficiencies cannot be higher than about 25% because of:

the second law of thermodynamics.

54. A current flowing through a wire gives rise to:

A magnetic field circulating around the wire.

55. You are in a spaceship moving past Earth at nearly lightspeed. You observe Mort on Earth. You measure his mass, pulse rate, and size. They are different because:

Mass has increased, pulse rate has slowed down, and size is reduced along the direction of motion.

56. When light passes through a double slit and falls on a screen:

Constructive interference occurs where the crests of one wave arrive with the crests of the other.

57. In the Electric Motor mini-lab, the role of the magnet is:

Its magnetic field applies a sideways force to the wire only when a current is flowing in the wire.

58. The relationship E = mc^2 applies to:

All forms of energy.

59. The approximate 14C content of the remains of a saber-toothed-tiger 24,000 years later would be:

1/16 gram.

60. Which of the following is not a heat engine?

hydro-electric generating plant.

61. Explain why, in terms of photons, ultraviolet light can damage cells in your skin but visible light cannot:

Ultraviolet photons have more energy.

62. The naturally-occurring isotope that will sustain a fission chain reaction is:

235U

63. Which one has the shortest wavelength, assuming that they all have the same speed?

electron

64. Which of the following is considered physically “real,” but is not made of atoms or other material particles?

electromagnetic fields

65. Hydrogen must be raised to a high temperature before it will fuse because:

high temperatures are needed to overcome the electric repulsion between hydrogen nuclei.

66. The nucleus 90Sr decays to 90Y. This is:

Beta decay

67. When a bar magnet is suddenly brought up to a coil of wire, the Faraday effect predicts that:

An electric current will tend to flow in the coil.

68. In the double-slit experiment with light, if only a single quantum of energy passes through, it will deposit:

at one small point within the white interference bands.

69. What happens to an electron’s wave packet if an accurate velocity measurement is performed?

It suddenly changes to a new wave packet having a very small uncertainty in velocity, but a large uncertainty in position.

70. If two identical plastic rods are rubbed with an identical cloth and then held at rest a short distance from each other, the force between them will be:

a repulsive electric force.

71. What sort of objects do not emit blackbody radiation?

Nonsense, all objects made of atoms emit some blackbody radiation.

72. According to current understanding, the proton is made of smaller particles known as:

quarks.

73. Which of the following are quanta of the electromagnetic field?

photons.

74. We never find isolated, individual quarks because:

the force between quarks is infinitely strong, so they cannot be separated from each other.

75. The Large Hadron Collider is:

a circular proton-proton accelerator.