Astronomy Exam 2
Suppose a high-flying jet cruises with a constant velocity when the thrust from its engines is a constant 80,000 N. What is the acceleration of the jet? What is the force of air resistance acting on the jet?
0 acceleration, 80,000 N
What total force will cause an object with a mass of 2kg to gain 5 meters per second every second?
10 Newtons
The Earth's distance from the Sun is defined to be 1 astronomical unit. Neptune is about 30 astronomical units from the Sun. An object in the Inner Oort Cloud might be at a distance from the Sun of
15000 astronomical units
The density of water is 1000kg/m3 while the density of iron is 7800kg/m3. Which of the following values is a plausible value for the density of a terrestrial planet?
5000 kg/m3
The density of water is 1000kg/mł while the density of rock is 3000kg/mł. Which of the following values is a plausible value for the density of a jovian planet?
700 kg/ml
The Inner Oort Cloud is located
Beyond the Kuiper belt
An annual meteor shower occurs when
Earth passes through comet debris
Who discovered Newton's First Law of Motion?
Galileo
The first space probe to reach the planet Mercury was
Mariner 10
Two blocks with the same mass are connected by a string and are pulled across a frictionless surface by a constant force. Will the two blocks move with constant velocity?
No, both blocks will be moving with constant acceleration.
When the velocity of an object does not change, what happens to its acceleration?
Nothing, it doesn't accelerate
The largest dwarf planet in the Kuiper Belt is
Pluto
A horse is pulling a cart along a road. Which of the following pairs of forces is an action-reaction pair?
The force of horse on the road and the force of the road on the horse
A book, weighing 10 Newtons, sits on a table. Which of the following pairs of forces is an action-reaction pair?
The force that the book exerts on the table and the force that the table exerts on the book
Which of the following statements about the moons of terrestrial planets is currently accepted?
They sometimes capture moons by accident
When an object is stationary, all of the forces acting on it are balanced.
True
Which of the following three systems is regarded as the most normal for a terrestrial planet?
Venus, with no moons at all.
The Inner Oort Cloud is
a doughnut-shaped region with objects above and below the plane of the solar system.
When the Earth passes through the orbit of a broken-up comet, we see
a meteor shower
Galileo's approach to science is best described as based on
active construction of simplified experiments
Mercury has
almost no atmosphere
The tail of a comet always points
away from the sun
When Galileo dropped a wooden ball and a heavier iron ball at the same time, he was expecting that
both balls would always hit at the exact same time
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, Galileo predicted that
both objects would hit the ground at the same time
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
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
The ion tail of a comet
consists of straight streamers
Most comets can best be described as
dirty snowballs or possibly flying icebergs
A meteoroid is a medium-sized rock that is
drifting in space
Comets usually follow orbits which are
elliptical with aphelia far outside the orbit of Mars.
The Oort Cloud is located
far beyond the orbit of Pluto
The International Space Station (ISS) is in a roughly circular orbit near the surface of the Earth, moving at around 5 miles per second. Suppose the Space Shuttle pushes it and quickly increases its speed to 6 miles per second. The ISS will then
follow an ellipse and then as the spacecraft moves farther from Earth, it slows down. Then it speeds up again as it returns to its starting point.
The density of rock is about 3000 kg/m3. The density of the Earth is
greater than 3000 kg/m3 because the Earth has an iron core
Comets are usually made of
ice and possibly frozen gas
Kuiper Belt objects are usually made of
ice and possibly frozen gas
The dust tail of a comet
is curved and fuzzy-looking
If the acceleration of an object is zero, its speed
is not changing
Galileo said that a moving object with nothing pushing or pulling on it will always
keep moving at the current speed or will stay at rest
The Law of Inertia states that a moving object will
keep moving unless it's acted upon by an external force
The jovian planets typically have
large systems of moons
You hear a loud noise outside and go outside to find a smoking rock embedded in your driveway underneath your wrecked car. The object is probably a
meteorite
Comets that originate in the Inner Oort Cloud would be expected to have orbits that are
mostly close to the plane of the solar system
When a bullet is fired from a gun, the bullet keeps moving after it leaves the gun barrel because
no force stops it
The distance from the Earth to the Sun is
one astronomical unit
The radiant of a meteor shower is the
point in the sky the meteors seem to be coming from
The presence of frozen water on Mercury is
possible because it has no axial tilt so that its poles never face the Sun
Space probes often visit several planets before getting to their final destinations. The main reason they do this is to
reduce the amount of rocket fuel needed
Asteroids are usually made of
rock and possibly iron
Aristotle said that a moving earthly object with nothing pushing or pulling on it will always
slow down and stop
When Galileo dropped a wooden ball in an experiment and a heavier iron ball at the same time, he found that
sometimes the wooden ball hit first and sometimes the iron ball hit first
According to Galileo, a thrown spear keeps moving after it has left the spear thrower's hand because
the force of friction within the air is not enough to stop the spear
According to Aristotle, a thrown spear keeps moving after it has left the spear thrower's hand because
the force of the air disturbed by the spear keeps it in motion
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 predicted that
the heavier object would hit the ground long before the lighter one
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
During a meteor shower, shooting stars seem to be coming from
the radiant
