Astronomy Exam 2
Suppose the spacecraft has a total mass of 5000kg and sunlight exerts a total force of 5N on the sail. What will be the acceleration of the spacecraft?
0.001m/s2
An ion rocket engine produces 50 Newtons of thrust. What acceleration can it give to a space probe with a mass of 10,000kg?
0.005 m/s2
The average radius of the Earth's orbit is
1.0 au
Suppose that you try to lift an object by exerting an upward force of 5 newtons on it. if gravity exerts a force of 20 newtons downward on the object, what is the total force on the object?
15 newtons downward
The first successful soft landing on the Moon was Surveyor 1 in
1966
If the planets are numbered from 1 to 8, going outward from the Sun, the planet Mars is number
4 (Uranus is number 7) (Neptune is 8)
What total force will cause an object with a mass of 50kg to gain 1 meter per second every second?
50 newtons
The density of water is 1000kg/m3, the density of rock is about 3000kg/m3, and the density of iron is 7800kg/m3. Which of the following densities is closest to the average density of the Earth?
5200kg/m3
Which of the following types of objects include things that could reasonably be described as "flying rocks" or, for larger ones, "flying mountains"?
Asteroids
Most Kuiper Belt Objects are similar in composition to
Comets
Which of the following planets or moons has an atmosphere where temperature and pressure permit all three forms of water?
Earth
Which of the following objects has no magnetic field at all?
Earth's Moon
Which of the following conclusions is appropriate?
Galileo really did the experiment
Which of the following schemes will work?
Increase its speed to 6 miles per second to put it on a rising path and give it another speed boost when its distance from the Earth stops increasing
The Apollo program was thought to be part of a "race to the Moon" with the Soviet Union. Actually
It was a close race. The Soviets actually built a Moon rocket and tested it
Which of the following objects has no overall magnetic field except for small regions due to magnetized ore deposits?
Mars
Which of the following planets has a moon that rises in the West?
Mars
Which of these planets has a solar day that is very close to an Earth day in length?
Mars
The Asteroid Belt is between the orbits of
Mars and Jupiter
Which of the following planets can be said to have almost no atmosphere?
Mercury
Which of these Mars rovers has been operating on the surface of Mars for fourteen years so far (as of 2018)?
Opportunity (Curiosity for six years)
The first space probe to place a robotic rover on the surface of Mars was
Pathfinder
Which of these Moons rises in the West as seen from its primary planet?
Phobos
The first space probes to land on another planet were from the
Russian Venera series
Why couldn't we just fly a Space Shuttle to the Moon for at least a fly-by?
The Space Shuttle did not have enough fuel to reach escape velocity
Why don't we just shoot all of our really nasty waste products into the Sun where they could not possibly bother anyone?
The Sun is actually the hardest part of the Solar System to get to from here
The capture theory, in which our Moon forms separately and is captured by the Earth, became popular when computer models showed that such a capture would have been possible
The capture theory was dropped partly because it predicts that the Moon should have hydrated rocks and it does not
You are standing in an elevator that is accelerating upward at 1m/s2. Which of the following pairs of forces is an action-reaction pair that have to be exactly equal and opposite to each other?
The force that the floor of the elevator exerts on you and the force that you exert on the floor of the elevator
Water ice can be found on all but one of these planets. Which one has no ice?
Venus
Which of the following planets has no magnetic field (and highest surface temperature) of any kind?
Venus
Which of the following planets has no moons at all?
Venus
Which of the following planets or moons has an atmosphere with about 90 times the surface pressure of Earth's
Venus
the ancient greeks thought that
a heavy object should fall faster than a lighter object because the heavy object is pulled down with more force
As of 2009, of these six programs
all except Russia have sent probes or orbiters to the Moon
In comparison to Kepler's Laws of Planetary Motion, Newton's theory of Universal Gravitation predicted
almost the same motions but with corrections (but with small corrections due to the gravitational attractions between different planets)
Mars has
an atmosphere of carbon dioxide with about 1% the surface pressure of Earth's
On the present surface of Mars, water has been confirmed to exist
as ice at the poles and water vapor in the atmosphere
On Earth, you might find a temperature of 59F on a Spring or Fall day in the temperature zone. On Mars, you might expect that temperature
at noon near the equator
For a planet to have substantial amounts of liquid water on its surface, it must have
atmospheric pressure above the triple point of water
Space probes often use gravitational slingshot maneuvers. The main purpose of these maneuvers is to
change the direction and speed of the probe without using rockets
Milankovich cycles refer to
changes in the intensity of sunlight due to shifts in both the Earth's orbit and rotation axis.
The currently accepted theory of how the Moon formed is the
collision theory
Which of the following objects would be most likely to have a long elliptical orbit that takes it from far outside the orbit of Mars to a close approach to the Sun?
comet
Relative to the distant stars, Mercury
completes 1.5 rotations each time it orbits the Sun. (Venus completes less than one full rotation)
Apollo 11 made the first
crewed landing on the Moon (1969)
Comets usually follow orbits which are
elliptical with aphelia far outside the orbit of Mars.
A rocket that leaves the Earth's atmosphere at a speed of 8 miles per second will
escape from the Earth's gravity forever
The magnetic field of Mars is
essentially zero
The shortest Earth-Sun distance (and highest intensity sunlight) currently occurs
every January
Suppose that a spacecraft is in a roughly circular orbit near the surface of the Earth, moving at around 5 miles per second. Suppose the spacecraft flips over backwards and fires its rocket engine to slow its speed to 4.96 miles per second. The spacecraft will then
follow an ellipse that descends a bit and then rises again (slows its speed again by a bit when its distance from the Earth stops decreasing)
Free falling objects with different masses fall with the same acceleration because
gravity exerts more force on the more massive object
Mercury rotates so that it
has a solar day that last for two complete orbits around the Sun.
The force of gravity explains
how the tides work but not how lightning works.
The statement that lunar material is much "dryer" than Earth material refers to the absence of
hydrated minerals
The circular structures on the surface of the Moon are the result of
impacts
A model in which the Moon forms from the same rotating cloud of gas and dust as the Earth would predict that the Moon's orbit should be
in the plane of the Earth's equator
When Newton calculated the magnitude and direction of the acceleration for a planet that was following Kepler's Laws, he found that the direction of the acceleration was
inversely proportional to the square of the planet's distance from the Sun
The Earth's Moon
is 1/4 the size of the Earth, which is unusually large for a moon
The Moon's orbit around the Earth
is elliptical enough to give us an annular solar eclipse when the Moon is near its apogee.
The gravitational attraction of the Earth for other objects,
is smaller for objects farther from the Earth but never vanishes entirely
The law of inertia states that a moving object will
keep moving if no force acts on it
The Lunar Maria are thought to have been caused by ancient
lava flows from large impacts
Compared to the rest of the Lunar surface, the Lunar Maria are
lower and younger
When the rocket engine in a spaceship stops firing, the spaceship keeps moving because
no force stops it
The observed magnetic field of Mercury is surprising because it was expected to have
no magnetic field at all because it rotates so slowly
It is expected that a normal terrestrial planet, with no accidental encounters that could add or subtract moons, should have
no moon
The moons of Mars are
not large enough to be spherical
When Newton's Laws were applied to predict the exact motion of the planet Uranus, the prediction failed to agree with very precise measurements. This failure led to the discovery
of the Plant Neptune
The Moon rotates on its axis relative to the distant stars
once every sidereal month
The phase diagram for water is presented on a graph with axes for temperature and
pressure
The Earth's magnetic field plays an essential role in
protecting the Earth from charged particles from the Sun (Van Allen Belts)
As viewed from the start Polaris, Venus
rotates clockwise and goes around the Sun counter-clockwise
The current model for the way that planets acquire magnetic fields requires which of the following combinations of things?
rotation and a core that contains a liquid electrical conductor
At present (within the last few hundred years) the orbit of the Earth around the Sun is
slightly elliptical so that the intensity of sunlight varies by 6 percent (Mars orbit varies by 40 percent)
A full cycle of day and night on Mars is called a "sol". In terms of 24 hours Earth days, a Martian sol is
slightly longer than one Earth day
Aristotle said that a moving earthly or "mundane" object with nothing pushing or pulling it will always
slow down
Since the last Apollo mission to the Moon and the last Soviet LUNA sample-return mission
spacecraft began to be sent there again by 1994
The ancient greeks connected the force exerted on an object to the object's
speed
The Soviet Union had a secret program to put the first human on the Moon. This program
test launched their Moon Rocket several times, but it blew up each time
When Newton calculated the magnitude of the acceleration of Earth's Moon relative to the Earth, and compared it to the acceleration of falling objects on the surface of the Earth, he found that
the Moon's acceleration was smaller
An astronomical unit is defined to be
the average distance from Earth to the Sun
for an object that is moving along a straight path, the acceleration is
the change in the object's speed divided by the time it takes
If you are told that an object that weighs 20 Newtons is raised a distance of 10 meters, you know that
the force of the gravity on the object is 20 newtons
A bazooka is actually a small rocker-launcher. The reason a bazooka does not have a recoil is that
the force on the rocket is exerted by the rocker exhaust and not be the launcher
Suppose that you drop two objects from the same height at the same time. Both objects are heavy enough to be unaffected by air resistance. If one object is twice as heavy as the other, Aristotle would predict that
the heavier object would hit the ground long before the lighter one
Viking 1 and 2 were sent to explore
the planet Mars
The force that acts on the combined object (mass driver plus asteroid) is actually exerted by
the rocks that the catapult throws
The Moon rotates on its axis so that it always keeps
the same side (far side) pointed away from the Earth
In Newton's theory of gravity, everything is attracted
to every other object in the universe
A planet that is following Kepler's Laws, accelerates
toward the Sun
Mercury rotates so that its sidereal day lasts for
two thirds of a complete orbit around the Sun (relative to the sun, just once during two complete orbits around the sun)
A planet whose atmospheric pressure is exactly at the triple point of water and whose surface temperature has a range that includes the triple point will have
water as ice or vapor, depending on the temperature
The Law of Inertia says that if an object is not acted on by any outside force, its acceleration
will always be zero (speed and direction of motion will not change)