AST 101 Exam 3 Questions And Accurate Answers
Recall that 1 foot = 12 inches. Therefore, 1 square foot = - ANSWER 144 square inches
Recall that 1 centimeter = 10 millimeters. Therefore, 1 cubic centimeter = - ANSWER 1000 cubic
millimeters
The surface area of a small moon is 50,000 square kilometers, which is equivalent to: -
ANSWER 50,000 x 1000^2 square meters
A large boulder has a volume of 1000 cubic meters and a mass of 3,200,000 kilograms. What is
the density of the boulder, in grams per cubic centimeter? - ANSWER 3.2 g/cm^3
In the Introduction to Parallax animation, notice that the parallax is greater (the apparent
movement is larger) for the person than for the trees, and that the mountains do not appear to
shift at all. Why? - ANSWER The amount of parallax depends on an object's distance, with
greater parallax for nearer objects.
Which statement best summarizes why stellar parallax occurs? - ANSWER We view nearby
stars from different positions in Earth's orbit at different times of year.
If the ancient Greeks had measured stellar parallax, they would have known that their belief in
an Earth-centered universe was wrong. Why didn't the ancient Greeks measure stellar
parallax? - ANSWER Even for the nearest stars, parallax angles are too small to measure with
the naked eye.
Based on their inability to detect stellar parallax, the ancient Greeks concluded that: - ANSWER
Either Earth is the center of the universe or stars are extremely far away
, Moreover, as the Parallax Angle animation shows, these measurements allow us to calculate
distances to these relatively nearby stars. If we hope to use parallax to measure distances to
even more-distant stars, which of the following telescopes would be most useful? - ANSWER A
telescope that orbits the Sun in the outer solar system
Before we can use parallax to measure the distance to a nearby star, we first need to know: -
ANSWER The Earth-Sun distance
Which of the following is a valid way of demonstrating parallax for yourself? - ANSWER Hold up
your hand in front of your face, and alternately close your left and right eyes.
What is the cause of stellar parallax? - ANSWER Earth's orbit around the Sun.
The more distant a star, the: - ANSWER Smaller its parallax angle
Approximately what is the parallax angle of a star that is 20 light-years away? - ANSWER 0.16
arcsecond
Suppose that a star had a parallax angle of exactly 1 arcsecond. Approximately how far away
would it be, in light-years? - ANSWER 3.3 light-years
If star A is closer to us than star B, then Star A's parallax angle is: - ANSWER Larger than that
of Star B
If the star Alpha Centauri were moved to a distance 10 times farther than it is now, its parallax
angle would - ANSWER Get smaller.
Rank (furthest distance from the sun): - ANSWER Pluto, Saturn, Jupiter, Mars, Earth, Mercury
Rank (highest mass): - ANSWER Sun, Jupiter, Earth, Mars, Mercury, Pluto
Recall that 1 foot = 12 inches. Therefore, 1 square foot = - ANSWER 144 square inches
Recall that 1 centimeter = 10 millimeters. Therefore, 1 cubic centimeter = - ANSWER 1000 cubic
millimeters
The surface area of a small moon is 50,000 square kilometers, which is equivalent to: -
ANSWER 50,000 x 1000^2 square meters
A large boulder has a volume of 1000 cubic meters and a mass of 3,200,000 kilograms. What is
the density of the boulder, in grams per cubic centimeter? - ANSWER 3.2 g/cm^3
In the Introduction to Parallax animation, notice that the parallax is greater (the apparent
movement is larger) for the person than for the trees, and that the mountains do not appear to
shift at all. Why? - ANSWER The amount of parallax depends on an object's distance, with
greater parallax for nearer objects.
Which statement best summarizes why stellar parallax occurs? - ANSWER We view nearby
stars from different positions in Earth's orbit at different times of year.
If the ancient Greeks had measured stellar parallax, they would have known that their belief in
an Earth-centered universe was wrong. Why didn't the ancient Greeks measure stellar
parallax? - ANSWER Even for the nearest stars, parallax angles are too small to measure with
the naked eye.
Based on their inability to detect stellar parallax, the ancient Greeks concluded that: - ANSWER
Either Earth is the center of the universe or stars are extremely far away
, Moreover, as the Parallax Angle animation shows, these measurements allow us to calculate
distances to these relatively nearby stars. If we hope to use parallax to measure distances to
even more-distant stars, which of the following telescopes would be most useful? - ANSWER A
telescope that orbits the Sun in the outer solar system
Before we can use parallax to measure the distance to a nearby star, we first need to know: -
ANSWER The Earth-Sun distance
Which of the following is a valid way of demonstrating parallax for yourself? - ANSWER Hold up
your hand in front of your face, and alternately close your left and right eyes.
What is the cause of stellar parallax? - ANSWER Earth's orbit around the Sun.
The more distant a star, the: - ANSWER Smaller its parallax angle
Approximately what is the parallax angle of a star that is 20 light-years away? - ANSWER 0.16
arcsecond
Suppose that a star had a parallax angle of exactly 1 arcsecond. Approximately how far away
would it be, in light-years? - ANSWER 3.3 light-years
If star A is closer to us than star B, then Star A's parallax angle is: - ANSWER Larger than that
of Star B
If the star Alpha Centauri were moved to a distance 10 times farther than it is now, its parallax
angle would - ANSWER Get smaller.
Rank (furthest distance from the sun): - ANSWER Pluto, Saturn, Jupiter, Mars, Earth, Mercury
Rank (highest mass): - ANSWER Sun, Jupiter, Earth, Mars, Mercury, Pluto
