AST Unit II – Flashcards

In winter, Earth's axis points toward the star Polaris. In spring: 1. the axis also points toward Polaris. 2. the axis points toward Vega. 3. the axis points toward the Sun.

When it is summer in Australia, the season in the United States is 1. winter. 2. summer. 3. spring.

If the Sun rises precisely due east: 1. you must be located at Earth's equator. 2. it must be the day of either the spring or fall equinox. 3. it must be the day of the summer solstice.

Based on what you have learned from your rankings in Parts A and B, which statement best describes how variation in the Earth-Sun distance affects the seasons? 1. Summer occurs when Earth is closer to the Sun and winter occurs when Earth is farther from the Sun. 2. The variation in Earth-Sun distance over the course of each year has virtually no effect on the seasons. 3. No matter where you live or what the seasons, it is generally hotter when Earth is closer to the Sun and colder when Earth is farther from the Sun.

You've now seen that Earth's varying distance cannot be the cause of our seasons. So what is the cause of the seasons? 1. The tilt of Earth's axis causes different portions of the Earth to receive more or less direct sunlight at different times of year. 2. The seasons are caused by variation in the amount of rainfall (or snowfall) in different places at different times of year. 3. The tilt of Earth's axis causes the Northern Hemisphere to be closer to the Sun than the Southern Hemisphere in summer, and vice versa in winter. 4. Earth's speed varies in its orbit around the Sun, giving us summer when Earth is moving fastest and winter when Earth is moving slowest.

Based on what you have learned from your rankings in Parts A and B, which of the following planets would you expect to have seasons most like Earth's? 1. Jupiter (axis tilt = 3.1°) 2. Mars (axis tilt = 25.2°) 3. Uranus (axis tilt = 97.9°)

Which of the following planets should have the most extreme seasons? 1. Neptune (axis tilt = 29.6°) 2. Jupiter (axis tilt = 3.1°) 3. Uranus (axis tilt = 97.9°) 4. Mars (axis tilt = 25.2°)

Which of the following planets has essentially no seasons at all? 1. Uranus (axis tilt = 97.9°) 2. Jupiter (axis tilt = 3.1°) 3. Neptune (axis tilt = 29.6°) 4. Mars (axis tilt = 25.2°)

If we have a new moon today, when we will have the next full moon? 1. in about a month 2. in about 2 weeks 3. in about 6 months 4. in about 1 week

We cannot see a new moon in our sky because _________. 1. it is above the horizon during the daytime 2. a new moon is quite near the Sun in the sky 3. no sunlight is illuminating the Moon 4. it is obscured by Earth's shadow

Lunar eclipses can occur only during a _________. 1. third quarter moon 2. new moon 3. full moon 4. first quarter moon

Suppose that instead of being inclined to Earth's orbit around the Sun, the Moon's orbit was in the same plane as Earth's orbit around the Sun. (Click "Show Moon with flat orbit" to see this situation.) In this hypothetical situation, approximately how many solar eclipses would occur each year? 1. 0 2. 1 3. 2 4. 12 5. 24

In reality, the Moon's orbit about Earth is tilted (by about 5°) with respect to Earth's orbit about the Sun. As a result, the actual number of solar eclipses that occur each year is approximately _____. 1. 0 2. 2 3. 12 4. 24

What conditions must exist for a solar eclipse to occur? 1. The only condition is that the phase of the Moon must be new. 2. The phase of the Moon must be new and the Moon must be passing through Earth's orbital plane. 3. The only condition is that the phase of the Moon must be full. 4. The phase of the Moon must be full and the Moon must be passing through Earth's orbital plane.

What conditions must exist for a lunar eclipse to occur? 1. The only condition is that the phase of the Moon must be new. 2. The phase of the Moon must be new and the Moon must be passing through Earth's orbital plane. 3. The only condition is that the phase of the Moon must be full. 4. The phase of the Moon must be full and the Moon must be passing through Earth's orbital plane.

If you could change the layout of the solar system, which of the following would cause a lunar eclipse to occur at least once every month in this hypothetical situation? 1. Make the Moon orbit Earth twice as fast. 2. Change the Moon's orbital plane so it tilts the opposite way. 3. Relocate the Moon to twice its current distance from Earth. 4. Change the Moon's orbital plane so it is in the same plane as Earth's orbit around the Sun.

Suppose you lived on the Moon. Which of the following would be true? 1. Your weight would be less than your weight on Earth, but your mass would be the same as it is on Earth. 2. Both your weight and your mass would be the same as they are on Earth. 3. Both your weight and your mass would be less than they are on Earth. 4. Your mass would be less than your mass on Earth, but your weight would be the same as it is on Earth.

A car is accelerating when it is 1. traveling on a straight uphill road at 30 miles per hour. 2. going around a circular track at a steady 100 miles per hour. 3. traveling on a straight, flat road at 50 miles per hour.

Which of the following statements is NOT one of Newton's Laws of Motion? 1. For any force, there always is an equal and opposite reaction force. 2. What goes up must come down. 3. In the absence of a net force acting upon it, an object moves with constant velocity. 4. The rate of change of momentum of an object is equal to the net force applied to the object.

Which of the following examples describes a situation where a car is experiencing a net force? 1. The car is making a gradual turn. 2. The car is stopped on a hill. 3. The car is floating on a stationary boat. 4. The car is moving at constant speed.

Compared to their values on Earth, on another planet your 1. mass would be the same but your weight would be different. 2. weight would be the same but your mass would be different. 3. mass and weight would both be the same.

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

If Earth were twice as far from the Sun, the force of gravity attracting Earth to the Sun would be 1. half as strong. 2. twice as strong. 3. one-third as strong. 4. one-quarter as strong.

Suppose that the Sun shrank in size but that its mass remained the same. What would happen to the orbit of the Earth? 1. Earth's orbit would expand, and it would take more than one year to orbit the Sun. 2. Earth would change from a bound orbit to an unbound orbit and fly off into interstellar space. 3. Earth's orbit would be unaffected. 4. The size of Earth's orbit would shrink, and it would take less than one year to orbit the Sun.

If you actually performed and compared the two trials chosen in Part C, you would find that, while the basketball and marble would hit the ground at almost the same time, it would not quite be exact: The basketball would take slightly longer to fall to the ground than the marble. Why? 1. Because air resistance has a greater effect on the smaller ball. 2. Because gravity has a greater effect on the smaller ball. 3. Because air resistance has a greater effect on the larger ball. 4. Because gravity has a greater effect on the larger ball.

Einstein's theory, like Newton's, predicts that, in the absence of air resistance, all objects should fall at the same rate regardless of their masses. Consider the following hypothetical experimental results. Which one would indicate a failure of Einstein's theory? 1. Scientists dropping balls from the Leaning Tower of Pisa find that balls of different mass but the same size fall at slightly different rates. 2. Scientists dropping balls on the Moon find that balls of different mass fall at slightly different rates. 3. Scientists dropping balls from the Leaning Tower of Pisa find that balls of different size but the same mass fall at slightly different rates.

We say that Earth's axis has a tilt of 23.5 degrees, which means that 1. Earth's Northern Hemisphere is always tilted away from the sun at an angle of 23.5 degrees 2. Earth's Northern Hemisphere is always tilted toward the Sun at an an angle of 23.5 degrees 3. Earth's axis is tilted at an angle of 23.5 degrees compared to a line perpendicular (straight up and down) to its orbit

If the Northern Hemisphere were tilted 90 degrees toward the sun, which location would be warmer in the summer? 1. Arctic Circle 2. Florida 3. The equator 4. Antarctica

It is ________ when we see all of the Moon's daylight side and none of its night side. 1. waxing moon 2. full moon 3. new moon

The Moon's phase is ________ when we see half of the Moon's daylight side and half of its night side 1. half moon 2. full moon 3. new moon 4. first quarter or third quarter moon

We see a full moon in our sky only when ______ 1. Earth's shadow does not touch the Moon at all 2. Exactly half the Moon is illuminated by sunlight 3. the Moon and Sun are on opposite sides of Earth

We see about 3/4 of the Moon's face illuminated at waxing gibbous phase. What do we see about three to four days later? 1. A full moon 2. A half moon 3. A crescent moon

Which of the following correctly describes what we mean by "waxing" and "waning" phases of the Moon? 1. Waxing means we see phases in which we can see large craters on the Moon, and waning means phases in which we can't. 2. Waxing means we see less than half the moon illuminated, and waning means we see more than half 3. Waxing means that we see as the moon approaches full moon, and waning means phases that we see after full moon

When does a full moon appear near the western horizon? 1. Around the time of sunrise 2. Around the time of sunset 3. At noon 4. At midnight

A solar eclipse occurs when _________. 1. Earth's shadow falls on the Moon 2. the Sun's shadow falls on the Moon 3. the Moon's shadow falls on Earth

How often does a new moon occur? 1. Once a week 2. Once a month 3. Once a year

According to Newton's second law, the greater the force exerted on an object, the greater the object's ______. 1. Mass 2. Acceleration 3. Distance 4. Velocity

Where would you have to place a space probe between Mars and Earth, in order for the probe to experience a net (total) zero force? 1. Closer to Earth than to Mars 2. At the midpoint between Earth and Mars 3. Closer to Mars 4. It is impossible for the probe to experience a net zero force