AST 104 Test 1 With All Correct & 100% Verified
Answers |Actual Complete Exam |Already Graded A+
(Just Released)
Scientific notation ✔Correct Answer-a × 10^b
In any measurements of quantities, they are conventionally agreed-upon standard things ✔Correct
Answer-Units
The international standard units for science and probably the most common subset of these units
✔Correct Answer-SI or metric; MKS
MKS stands for ✔Correct Answer-Meters, Kilograms, Seconds
In the metric system, the prefixes kilo and centi indicate, respectively, multiplication by ✔Correct
Answer-1000 and 0.01 (remember KHDBDCM)
On the Kelvin temperature scale absolute zero is ✔Correct Answer-0 K
Physical units of measurement based only on universal physical constants. example speed of light = 1
✔Correct Answer-Natural Units
The mean distance from the Earth to the Sun in astronomical units (AU) is ✔Correct Answer-1 AU
A light-year is ✔Correct Answer-the distance
light travels in one year
A parsec is ✔Correct Answer-about 3 light-years
A parsec is a unit typically used for ✔Correct Answer-nearest-neighbor interstellar distances
A kiloparsec (Kpc) is a unit typically used for ✔Correct Answer-INTRAgalactic distances
Name three astronomically relevant physical scales ✔Correct Answer-The Earth-Moon distance,
the Earth-Sun distance, and the radius of the Galactic disk
Ex-planet Pluto's mean distance from the Sun is about ✔Correct Answer-40 AU
About how many kilometers are there in a light-minute? Recall the speed of light c = 2.99792458 ×
1010 cm/s ✔Correct Answer-1.8 × 107 km
The length of a Julian year of 365.25 days in seconds is ✔Correct Answer-about π × 107 s
The Earth rotates once a day and has an equatorial radius of 6378 km. What is the speed of a point at
the POLES relative to a reference frame orbiting with the Earth, but not rotating with the Earth?
✔Correct Answer-Zero velocity
, The acceleration due to gravity of a free-falling object near the surface of the Earth is g = 9.8 m/s^2 .
If an object falls from rest and one can neglect air resistance, what is its speed after 3 seconds
✔Correct Answer-v = gt = 9.8 m/s^2 × 3 s = 29.4 ≈ 30 m/s
How long does it take light to travel from the Moon to the Earth? ✔Correct Answer-1.28 seconds
The star Proxima Centauri is 4.2 light-years from the Earth. How many years does it take for light to
travel from Proxima to Earth ✔Correct Answer-4.2 years
How many degrees in a circle, arcminutes in a degree, and arcseconds in an arcminute? ✔Correct
Answer-360, 60, 60
A fist at arm's length for the average person spans about how many degrees? ✔Correct Answer-
About 10°
An Earth-orbiting artificial satellite is passing by Polaris. At closest approach it is about a fist at arm's
length away in angular separation. What is the closest approach in angle and in spatial separation?
✔Correct Answer-About 10°, spacial separation is negligible
Two stars are a fist width's apart on the sky. (The fist is at arm's length.) What is the angular
separation of the two stars? How far apart are they in space? ✔Correct Answer-The angular
separation is about 10◦ . The spatial separation CANNOT be determined from the given information
A straight line on a linear plot represents a/an ________ function. ✔Correct Answer-linear
A curve on a linear plot that decreases as 1 over the square of the horizontal axis coordinate
represents a/an function ✔Correct Answer-inverse-square
If a function goes to infinity at x = 0, it ✔Correct Answer-may be an inverse-square function
On a standard logarithmic or log plot, an axis unit is ✔Correct Answer-a power of ten
On a base-10 logarithmic scale, the unit is a power of ✔Correct Answer-10
the eccentricity of a circular orbit ✔Correct Answer-0
Most comets that are gravitationally bound to the Sun have very elliptical orbits. This means that
most bound comet orbits have eccentricities that are ✔Correct Answer-greater than 0 in some
sense, but less than 1
The eccentricity of a body in orbit about the Sun is 0.20. How does its distance from the Sun vary
✔Correct Answer-At APHELION the body is 20 % farther from the Sun than the standard mean
distance. At PERIHELION it is 20 % closer to the Sun than the standard mean distance
There are two gravitationally-bound bodies isolated in space. Describe their motion ✔Correct
Answer-The two bodies orbit their joint center of mass in ellipses.
To very good approximation, the planets move in ✔Correct Answer-elliptical orbits with the Sun at
one focus of the ellipse
Answers |Actual Complete Exam |Already Graded A+
(Just Released)
Scientific notation ✔Correct Answer-a × 10^b
In any measurements of quantities, they are conventionally agreed-upon standard things ✔Correct
Answer-Units
The international standard units for science and probably the most common subset of these units
✔Correct Answer-SI or metric; MKS
MKS stands for ✔Correct Answer-Meters, Kilograms, Seconds
In the metric system, the prefixes kilo and centi indicate, respectively, multiplication by ✔Correct
Answer-1000 and 0.01 (remember KHDBDCM)
On the Kelvin temperature scale absolute zero is ✔Correct Answer-0 K
Physical units of measurement based only on universal physical constants. example speed of light = 1
✔Correct Answer-Natural Units
The mean distance from the Earth to the Sun in astronomical units (AU) is ✔Correct Answer-1 AU
A light-year is ✔Correct Answer-the distance
light travels in one year
A parsec is ✔Correct Answer-about 3 light-years
A parsec is a unit typically used for ✔Correct Answer-nearest-neighbor interstellar distances
A kiloparsec (Kpc) is a unit typically used for ✔Correct Answer-INTRAgalactic distances
Name three astronomically relevant physical scales ✔Correct Answer-The Earth-Moon distance,
the Earth-Sun distance, and the radius of the Galactic disk
Ex-planet Pluto's mean distance from the Sun is about ✔Correct Answer-40 AU
About how many kilometers are there in a light-minute? Recall the speed of light c = 2.99792458 ×
1010 cm/s ✔Correct Answer-1.8 × 107 km
The length of a Julian year of 365.25 days in seconds is ✔Correct Answer-about π × 107 s
The Earth rotates once a day and has an equatorial radius of 6378 km. What is the speed of a point at
the POLES relative to a reference frame orbiting with the Earth, but not rotating with the Earth?
✔Correct Answer-Zero velocity
, The acceleration due to gravity of a free-falling object near the surface of the Earth is g = 9.8 m/s^2 .
If an object falls from rest and one can neglect air resistance, what is its speed after 3 seconds
✔Correct Answer-v = gt = 9.8 m/s^2 × 3 s = 29.4 ≈ 30 m/s
How long does it take light to travel from the Moon to the Earth? ✔Correct Answer-1.28 seconds
The star Proxima Centauri is 4.2 light-years from the Earth. How many years does it take for light to
travel from Proxima to Earth ✔Correct Answer-4.2 years
How many degrees in a circle, arcminutes in a degree, and arcseconds in an arcminute? ✔Correct
Answer-360, 60, 60
A fist at arm's length for the average person spans about how many degrees? ✔Correct Answer-
About 10°
An Earth-orbiting artificial satellite is passing by Polaris. At closest approach it is about a fist at arm's
length away in angular separation. What is the closest approach in angle and in spatial separation?
✔Correct Answer-About 10°, spacial separation is negligible
Two stars are a fist width's apart on the sky. (The fist is at arm's length.) What is the angular
separation of the two stars? How far apart are they in space? ✔Correct Answer-The angular
separation is about 10◦ . The spatial separation CANNOT be determined from the given information
A straight line on a linear plot represents a/an ________ function. ✔Correct Answer-linear
A curve on a linear plot that decreases as 1 over the square of the horizontal axis coordinate
represents a/an function ✔Correct Answer-inverse-square
If a function goes to infinity at x = 0, it ✔Correct Answer-may be an inverse-square function
On a standard logarithmic or log plot, an axis unit is ✔Correct Answer-a power of ten
On a base-10 logarithmic scale, the unit is a power of ✔Correct Answer-10
the eccentricity of a circular orbit ✔Correct Answer-0
Most comets that are gravitationally bound to the Sun have very elliptical orbits. This means that
most bound comet orbits have eccentricities that are ✔Correct Answer-greater than 0 in some
sense, but less than 1
The eccentricity of a body in orbit about the Sun is 0.20. How does its distance from the Sun vary
✔Correct Answer-At APHELION the body is 20 % farther from the Sun than the standard mean
distance. At PERIHELION it is 20 % closer to the Sun than the standard mean distance
There are two gravitationally-bound bodies isolated in space. Describe their motion ✔Correct
Answer-The two bodies orbit their joint center of mass in ellipses.
To very good approximation, the planets move in ✔Correct Answer-elliptical orbits with the Sun at
one focus of the ellipse
