PS 224 Astronomy Ch 4
If your mass is 60 kg on Earth, what would your mass be on the Moon?
60 kg
Considering Einstein's famous equation, E = mc2, which of the following statements is true?
A small amount of mass can be turned into a large amount of energy.
If you double the mass of fusion material in a hydrogen bomb, you quadruple the amount of energy generated.
False
Galileo observed which of the following phases of Venus?
Cresent, New, Full, Gibbous. All the above
Doubling the distance between two objects halves the gravitational force between them.
False
Kepler deduced his laws of planetary motion once Newton had published his universal law of gravitation.
False
Speed and velocity are the same thing.
False
The escape velocity from Earth is greater for larger rockets than for small ones.
False
There is no gravity in space.
False
When energy is converted from one form to another, a tiny amount is inevitably lost.
False
When you experience a downward gravitational force from the Earth, the Earth experiences a weaker upward gravitational force from you.
False
Why did Tycho conclude that the Sun revolves around the Earth?
He could not detect the parallax of stars expected if the Earth revolves around the Sun.
How does the Space Shuttle take off?
Hot gas shoots out from the rocket and, by conservation of momentum, the shuttle moves in the opposite direction.
Consider the elliptical orbit of a comet around the Sun. Where in its orbit does it have the largest amount of total orbital energy?
It always has the same total orbital energy.
Where does the energy come from that your body uses to keep you alive?
It comes from the foods you eat.
What is stellar parallax?
It is the slight back-and-forth shifting of star positions that occurs as we view the stars from different positions in Earth's orbit of the Sun.
In the Ptolemaic model of the solar system, Venus should exhibit which of the following phases?
New and Crescent
Changing the orbit of a spacecraft by firing thrusters is an example of
Newton's third law of motion.
What discoveries or further ideas were most critical for Copernicus' hypothesis that the planets orbit the sun to be promoted to a theory?
Observation of the moons of Jupiter, and Observation of Venus' phases
What is the celestial sphere?
The celestial sphere is a representation of how the entire sky looks as seen from Earth.
A planet is orbiting a star. Which of the following statements is true for the acceleration and gravitational forces experienced by the star and the planet?
The acceleration of the planet is much more than the acceleration of the star, but the force on the star is the same but opposite the force on the planet.
Which of the following statements does not use the term angular size or angular distance correctly?
The angular distance between those two bright stars in the sky is about 2 meters.
Which of the following best describes why we have seasons on Earth?
The tilt of Earth's axis causes different portions of the Earth to receive more or less direct sunlight at different times of year.
Which of the following statements correctly describes the law of conservation of energy?
The total quantity of energy in the universe never changes.
The Moon is constantly falling toward Earth.
True
Tidal friction caused by Earth's stretching from the Moon's gravity is gradually slowing down the rotation of Earth.
True
Which of the following critical features of the heliocentric model leads to Venus exhibiting a full range of phases?
Venus passes on the far-side of the sun from the Earth's perspective.
Newton's second law states: sum of forces = mass × acceleration. If a known force was applied to an object with a known mass, how would you predict that object's acceleration?
acceleration = sum of forces / mass
The astronauts feel weightless in the International Space Station, which orbits the Earth once every 90 minutes. Why?
because they and the space station are both falling around the Earth
At which lunar phase(s) are tides least pronounced (e.g., the lowest high tides)?
both first and third quarters
Gasoline is useful in cars because it has
chemical potential energy.
Stars that are visible in the local sky on any clear night of the year, at any time of the night, are called ________.
circumpolar
Suppose an object is moving in a straight line at 50 mi/hr. According to Newton's first law of motion, the object will
continue to move in the same way until it is acted upon by a force.
The allowed shapes for orbits under the force of gravity are
ellipses, parabolas, and hyperbolas.
As an interstellar cloud of hydrogen gas shrinks in size, its rate of rotation
increases, because its angular momentum is conserved.
According to the universal law of gravitation, the force due to gravity is
inversely proportional to the square of the distance between objects.
Which of the following is the reason for the solar day being longer than a sidereal day?
the combined effect of the rotation of Earth and its orbit about the Sun
The amount of gravitational potential energy released as an object falls depends on
the distance it falls.
What is the ecliptic?
the path the Sun appears to trace around the celestial sphere each year
What is the saros cycle?
the roughly 18-year cycle over which the pattern of eclipses repeats
The tides on Earth are an example of
the universal law of gravitation.
The point directly over your head is called ________.
the zenith
If a gas cloud shrinks, its gravitational potential energy is converted into
thermal energy and radiative energy.
As long as an object is not gaining or losing mass, a net force on the object will cause a change in
velocity
The force of gravity is an inverse square law. This means that, if you double the distance between two large masses, the gravitational force between them
weakens by a factor of 4.