Physics Chapter 9

65) If an object is placed exactly halfway between Earth and the Moon, it would fall toward the A ) Earth. B) Moon. C) neither of these.

A) Earth. (Gravitational Fields)

35) Which is most responsible for Earth's ocean tides? A) Moon B) Sun C) both contribute equally.

A) Moon (Ocean Tides)

59) The concept of force is fundamental to A) Newton's theory of gravitation. B) Einstein's theory of gravitation. C) both of these D) neither of these.

A) Newton's theory of gravitation. (Gravitational Fields)

43) During an eclipse of the Sun the high ocean tides on Earth are A) extra high. B) extra low. C) not significantly different.

A) extra high. (Ocean Tides)

58) The direction of a gravitational field is A) in the same direction as gravitational attraction. B) away from the center of gravity of an object. C) opposite to the direction of gravitational attraction.

A) in the same direction as gravitational attraction. (Gravitational Fields)

25) When you weigh yourself on a bathroom scale on a slight incline instead of a level surface, your weight reading on the scale will be A) less. B) no different. C) more.

A) less. (Weight and Weightlessness)

12) The difference between Newton's law as a proportion and an equation involves A) the constant G. B) the equal sign. C) one being a vector and the other not. D) magnitude and direction.

A) the constant G. (Universal Gravitational Constant, G)

80) Planets wobble in their orbits due to A) the gravitational attraction to other planets. B) uncertainties in the inverse-square law. C) elliptical-orbit quirks. D) all of these. E) none of these.

A) the gravitational attraction to other planets. (Universal Gravitation)

60) An asteroid exerts a 360-N gravitational force on a nearby spacecraft. The 360-N force on the spacecraft is directed A) toward the asteroid. B) away from the asteroid. C) toward the Sun.

A) toward the asteroid. (Gravitational Fields)

14) In comparison with other fundamental forces, the universal gravitational constant G indicates that gravity is . A) very weak. B) strong. C) very strong.

A) very weak. (Universal Gravitational Constant, G)

44) The Earth is closer to the Sun in January than in July, which accounts for the fact that the highest high tides in the Northern Hemisphere occur in A) winter. B) spring. C) summer. D) none of these.

A) winter. (Ocean Tides)

34) Which pulls on the oceans of Earth with a greater force? A) Moon B) Sun C) both pull the same.

B) Sun (Ocean Tides)

57) Earth's gravitational field extends A) only above and beyond Earth's surface and cancels inside Earth. B) both inside and outside Earth and throughout the entire universe. C) neither of these.

B) both inside and outside Earth and throughout the entire universe. (Gravitational Fields)

19) If Earth's mass decreased to one-half its original mass with no change in radius, then your weight would A) decrease to one-quarter. B) decrease to half. C) stay the same. D) none of these.

B) decrease to half. (Inverse-Square Law)

82) Pluto is classified by as a A) full-fledged planet. B) dwarf planet. C) moon.

B) dwarf planet. (Universal Gravitation)

2) According to Newton, the greater the masses of interacting objects, the A) less the gravitational force between them. B) greater the gravitational force between them. C) greater the force between them by the square of the masses.

B) greater the gravitational force between them. (Universal Law of Gravity)

36) The main reason ocean tides exist is that Moon's pull is stronger A) than the pull of the Sun. B) on water closer to it than on water farther away. C) on Earth's oceans than on Earth itself. D) all of these.

B) on water closer to it than on water farther away. (Ocean Tides)

73) Which rocket would require more fuel? A) one going from the Moon to Earth. B) one going from Earth to the Moon. C) both the same.

B) one going from Earth to the Moon. (Gravitational Fields)

69) Half-way to the center of a planet of uniform density, your weight compared to that at the surface would be A) one-quarter. B) one-half. C) three-quarters. D) the same as at the surface. E) zero.

B) one-half. (Gravitational Fields)

3) According to Newton, when the distance between two interacting objects doubles, the gravitational force is A) half. B) one-quarter. C) the same. D) twice as much. E) four times as much.

B) one-quarter. (Universal Law of Gravity)

1) Newton discovered A) gravity. B) that gravity is universal. C) neither of these.

B) that gravity is universal. (Universal Law of Gravity)

26) If you jounce up and down on a bathroom scale, what varies on the scale reading is A) mg. B) the normal force. C) both of these. D) neither of these.

B) the normal force. (Weight and Weightlessness)

29) Inside a freely-falling runaway elevator, your A) acceleration is zero. B) weight is zero. C) gravitational interaction with Earth is zero. D) all of these. E) none of these.

B) weight is zero. (Weight and Weightlessness)

30) Inside a freely-falling elevator, you would have no A) gravitational force on you. B) weight. C) both of these. D) neither of these.

B) weight. (Weight and Weightlessness)

24) Your weight is the force A) due to gravity only. B) you exert against a supporting surface. C) equal to your normal force on any surface.

B) you exert against a supporting surface. (Weight and Weightlessness)

5) What is the force of gravity on a 500-N woman standing on Earth's surface? A) 50 N. B) 250 N. C) 500 N. D) 5000 N. E) none of these.

C) 500 N. (Universal Law of Gravity)

13) The universal gravitational constant G was first measured A) before Newton's time. B) by Newton himself. C) after Newton's time.

C) after Newton's time. (Universal Gravitational Constant, G)

56) Surrounding a magnet is a magnetic field. Surrounding an electron is an electric field. Surrounding Earth is A) an alteration in space in which mass experiences a force. B) a gravitational field. C) both of these. D) neither of these.

C) both of these. (Gravitational Fields)

83) The identities of dark energy and dark matter are A) unknown at this time. B) subjects of intense astronomical interest. C) both of these. D) neither of these.

C) both of these. (Universal Gravitation)

42) On each given day and location, tides rise and fall at A) about the same time. B) exactly the same time. C) different times. D) ever increasing rates daily.

C) different times. (Ocean Tides)

17) As two objects moving toward each other due to gravity get closer, the acceleration of each A) decreases. B) remains constant. C) increases.

C) increases. (Inverse-Square Law)

76) When a star collapses to form a black hole, its mass A) increases. B) decreases. C) remains the same.

C) remains the same. (Black Holes)

74) A black hole is A) an empty region of space with a huge gravitational field. B) at the center if all stars. C) the remains of a giant star that has undergone gravitational collapse.

C) the remains of a giant star that has undergone gravitational collapse. (Black Holes)

37) Tidal forces in general are the result of A) two or more sources of gravitation. B) a combination of any kind of forces acting on a body. C) unequal forces acting on different parts of a body. D) the inverse-square law. E) unequal fluid flow.

C) unequal forces acting on different parts of a body. (Ocean Tides)

79) An outcome of universal gravitation is that A) planets aren't cubes with sharp corners. B) its discovery prompted other laws of nature. C) prediction and discovery of planets. D) all of these.

D) all of these. (Universal Gravitation)

38) Tides caused mainly by the Moon occur in Earth's A) oceans. B) atmosphere. C) interior. D) all of these.

D) all of these. (Ocean Tides)

66) How far must one travel to escape Earth's gravitational field? A) to a region above Earth's atmosphere B) to a region well beyond the Moon C) to a region beyond the solar system D) forget it; you can't travel far enough.

D) forget it; you can't travel far enough. (Gravitational Fields)

18) When the distance between two stars decreases by one-third, the force between them A) decreases by one-third. B) decreases by one-half. C) increases to twice as much. D) increases to nine times as much. E) none of these.

D) increases to nine times as much. (Inverse-Square Law)

75) The factor most directly responsible for making a black hole invisible is its A) size. B) mass. C) color. D) surface escape velocity. E) none of these.

D) surface escape velocity. (Black Holes)

70) Half-way to the center of a completely hollow planet with a thin uniform shell, your weight would be A) one-quarter of your weight on the surface. B) one-half of your weight on the surface. C) three-quarters of your weight on the surface. D) the same as at the surface. E) zero. Answer:

E) zero. (Gravitational Fields)