CH9 PSY HW

Which of the following quantities would be acceptable representations of weight? 1`12.0 lbs 2`0.34 g 3`120 kg 4`1600 kN 5`0.34 m 6`411 cm 7`899 MN

1`12.0 lbs 4`1600 kN 7`899 MN

If Earth shrank with no change in its mass, what would happen to your weight at the surface? 1`It would increase. 2`It would decrease at first and then increase. 3`It would decrease. 4`It would stay the same.

1`It would increase.

What would the magnitude of the gravitational field be anywhere inside a hollow, spherical planet? 1`Zero N/kg 2`A quarter of the surface value 3`Half the surface value 4`The same as the surface value

1`Zero N/kg

Suppose you are in an elevator. As the elevator starts upward, its speed will increase. During this time when the elevator is moving upward with increasing speed, your weight will be __________. 1`greater than your normal weight at rest 2`equal to your normal weight at rest 3`less than your normal weight at rest

1`greater than your normal weight at rest Increasing speed means acceleration, and when the elevator is accelerating upward you will feel a force pressing you to the floor, making your weight greater than your normal (at rest) weight.

The constant G in Newton's equation _______. 1`makes the units of measurement consistent 2`was measured by Newton 3`produces equilibrium 4`shows gravity to be a relatively huge force

1`makes the units of measurement consistent

Consider Earth and the Moon. As you should now realize, the gravitational force that Earth exerts on the Moon is equal and opposite to that which the Moon exerts on Earth. Therefore, according to Newton's second law of motion __________. 1`the Moon has a larger acceleration than Earth, because it has a smaller mass 2`Earth has a larger acceleration than the Moon, because it has a larger mass 3`the Moon and Earth both have equal accelerations, because the forces are equal

1`the Moon has a larger acceleration than Earth, because it has a smaller mass Newton's second law of motion, F=ma, means that for a particular force F, the product mass x acceleration must always be the same. Therefore if mass is larger, acceleration must be smaller, and vice versa.

Which of the following quantities represent mass? Check all that apply. 1`12.0 lbs 2`0.34 g 3`120 kg 4`1600 kN 5`0.34 m 6`411 cm 7`899 MN

2`0.34 g 3`120 kg

Why are all tides greatest at the time of a full Moon or new Moon? 1`At full Moon and new Moon, the tides from the Moon and the Sun partially cancel because they make a right angle with Earth. 2`At full Moon and new Moon, the tides from the Moon and the Sun partially cancel because they are in line with Earth. 3`At full Moon and new Moon, the tides from the Moon and the Sun add because they are in line with Earth. 4`At full Moon and new Moon, the tides from the Moon and the Sun add because they make a right angle with Earth.

3`At full Moon and new Moon, the tides from the Moon and the Sun add because they are in line with Earth.

What great discovery followed finding perturbations in the planet Uranus? Pluto was discovered. 1`Newton's law of universal gravitation was discovered. 2`Einstein's theory of gravitation was discovered. 3`Neptune was discovered.

3`Neptune was discovered.

Why does the gravity in the Space Shuttle compare with the gravity on Earth the way it does? 1`The Space Shuttle is much farther away from the center of the Earth than the surface of the Earth. 2`The Space Shuttle is much closer to the center of the Earth than the surface of the Earth. 3`The Space Shuttle and the surface of the Earth are about the same distance from the center of the Earth.

3`The Space Shuttle and the surface of the Earth are about the same distance from the center of the Earth.

How does the gravity in the Space Shuttle compare with the gravity on Earth's surface? 1`The gravity in the Space Shuttle is much smaller than the gravity on Earth's surface. 2`The gravity in the Space Shuttle is much larger than the gravity on Earth's surface. 3`The gravity in the Space Shuttle is approximately equal to the gravity on the surface of the Earth

3`The gravity in the Space Shuttle is approximately equal to the gravity on the surface of the Earth

Predict how the upward force exerted on the feet by the scale will compare to the man's weight if the elevator is moving downward at a constant speed. 1`The upward force on the feet will be less than the man's weight. 2`The upward force on the feet will exceed the man's weight. 3`The upward force on the feet will be equal to the man's weight.

3`The upward force on the feet will be equal to the man's weight.

Predict how the upward force exerted on the feet by the scale will compare to the weight of the man if the elevator is moving upward at a constant speed. 1`The upward force on the feet will be less than the man's weight. 2`The upward force on the feet will exceed the man's weight. 3`The upward force on the feet will be equal to the man's weight.

3`The upward force on the feet will be equal to the man's weight.

When you weigh yourself on a bathroom scale in an elevator moving upward at constant velocity, are the springs in the scale more, or less, compressed? Moving downward at constant velocity? 1`There would be no more compression and no more expansion for both upward and downward motion. 2`More compressed while moving upward and less compressed while moving downward 3`More compressed while moving upward and while moving downward 4`Less compressed while moving upward and more compressed while moving downward

1`There would be no more compression and no more expansion for both upward and downward motion.

Predict how the upward force exerted on the feet by the scale will compare to the man's weight if the elevator is accelerating upward. 1`The upward force on the feet will be less than the man's weight. 2`The upward force on the feet will exceed the man's weight. 3`The upward force on the feet will be equal to the man's weight.

2`The upward force on the feet will exceed the man's weight.

An object is lifted from the surface of a spherical planet to an altitude equal to the radius of the planet. As a result, which of the following changes in the properties of the object take place? 1`mass increases; weight decreases 2`mass decreases; weight decreases 3`mass increases; weight increases 4`mass increases; weight remains the same 5`mass remains the same; weight decreases 6`mass remains the same; weight increases 7`mass remains the same; weight remains the same

5`mass remains the same; weight decreases

Calculate the force of gravity on a 1-kg mass if it were 6.4×10^6mabove Earth's surface (that is, if it were two Earth radii from Earth's center). Express your answer to two significant figures and include the appropriate units.

F = 2.4 N

Find the change in the gravitational force between two planets if the masses of both planets are doubled but the distance between them stays the same.

Fnew / F = 4

theres multi problem with a table on 19/20, going to skip those questions

SKIPPED

Why do the astronauts in the Space Shuttle float around? 1`The Space Shuttle is in free fall, so the shuttle and the astronauts inside it are continuously falling toward the Earth. They thus experience apparent weightlessness. 2`There is no gravity in the Space Shuttle because it is too far away from the center of the Earth. 3`There is no gravity in the Space Shuttle because it is completely enclosed and shielded from the effects of gravity due to the Earth.

1`The Space Shuttle is in free fall, so the shuttle and the astronauts inside it are continuously falling toward the Earth. They thus experience apparent weightlessness.

Predict how the upward force exerted on the feet by the scale will compare to the man's weight if the elevator is accelerating downward. 1`The upward force on the feet will be less than the man's weight. 2`The upward force on the feet will exceed the man's weight. 3`The upward force on the feet will be equal to the man's weight.

1`The upward force on the feet will be less than the man's weight.

Where do you weigh more--at the bottom of Death Valley or atop one of the peaks of the Sierra Nevada? Defend your answer. 1`You weigh more on the summit because the air buoys you up less. 2`You weigh more in Death Valley because you are closer to the center of Earth. 3`You weigh more on the summit, because the higher you go, the harder you fall. 4`You weigh more in Death Valley because more atmosphere pushes down on you.

2`You weigh more in Death Valley because you are closer to the center of Earth.

If you are standing on a scale in an elevator, what exactly does the scale measure? 1`your mass 2`the force you exert on the scale 3`the gravitational force exerted on you by Earth

2`the force you exert on the scale You probably recognize that neither your mass nor the gravitational force exerted on you change when you are in an elevator. The scale measures the force that is exerted on it, which in an elevator is a combination of the force due to your normal weight and a force due to the elevator's acceleration.

The gravitational field on the surface of the earth is stronger than that on the surface of the moon. If a rock is transported from the moon to the earth, which properties of the rock change? 1`mass only 2`weight only 3`both mass and weight 4`neither mass nor weight

2`weight only

Do tides depend more on the strength of gravitational pull or on the difference in strengths? Explain. 1`Tides depend on both the strength and the difference equally. 2`Tides depend only on the strength. 3`Tides depend only on the difference. 4`Tides depend weakly on the difference and strongly on the strength.

3`Tides depend only on the difference.

Suppose you are in an elevator that is moving upward. As the elevator nears the floor at which you will get off, its speed slows down. During this time when the elevator is moving upward with decreasing speed, your weight will be __________. 1`greater than your normal weight at rest 2`equal to your normal weight at rest 3`less than your normal weight at rest

3`less than your normal weight at rest Even though the elevator is still moving upward, the fact that its speed is slowing means that the acceleration is downward; the situation is rather like that of a ball that is still on its way up after you throw it, even though it is being pulled downward with the acceleration of gravity. Because the acceleration of the elevator is downward, your weight is lower than normal.

As you found in Part A, your weight will be greater than normal when the elevator is moving upward with increasing speed. For what other motion would your weight also be greater than your normal weight? 1`The elevator moves upward with constant velocity. 2`The elevator moves downward with constant velocity. 3`The elevator moves upward while slowing in speed. 4`The elevator moves downward while slowing in speed. 5`The elevator moves downward while increasing in speed.

4`The elevator moves downward while slowing in speed. When the elevator is moving downward, a downward acceleration would mean an increasing downward speed. Therefore, as your answer correctly states, an upward acceleration would mean a decreasing downward speed.

What happens to the force of attraction between two planets when the distance between them is doubled? 1`The force remains the same. 2`The force decreases to half. 3`The force doubles. 4`The force decreases to one quarter.

4`The force decreases to one quarter.