Astronomy Chapter 5 Exam
What total force will cause an object with a mass of 1kg to gain 5 meters per second every second?
5 Newtons
An ion rocket engine produces 1 Newton of thrust. What acceleration can it give to a space probe with a mass of 1000kg?
0.001 m/s²
Suppose that you lift an object by exerting an upward force of 12 Newtons on it. If gravity exerts a force of 10 Newtons downward on the object, what is the total force on the object?
2 Newtons
Who discovered Newton's First Law of Motion?
Galileo
Galileo predicted that dropping a wooden ball and an iron ball at exactly the same time would result in them hitting the ground at the same time, so long as air friction was negligible. When he actually did the experiment, the balls hit the ground very close together, but sometimes the wooden ball hit first and sometimes the iron one hit first. If we repeat his experiment today, we find exactly the same thing. Which of the following conclusions is appropriate?
Galileo really did the experiment
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
In comparison to Kepler's Laws of Planetary Motion, Newton's theory of Universal Gravitation predicted
almost the same motions but with corrections
Kepler's Laws
are explained by a force that attracts each planet to the Sun
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
Galileo's approach to understanding moving objects was to
build things that he could measure
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 that a rocket pushes it and quickly increases its speed to 6 miles per second. The ISS will then
follow an ellipse that rises and then descends again
A rocket that leaves the Earth's atmosphere at a speed of 4 miles per second will
follow an elliptical path that is partly below the surface of the Earth
Freely falling objects with different masses fall with the same acceleration because
gravity exerts more force on the more massive object
The force of gravity explains
how the tides work but not how lightning works
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 same speed
The Law of Inertia states that a moving object will
keep moving if no force acts on it
A unit of mass is the
kilogram
Aristotle said that a moving earthly or `mundane' object with nothing pushing or pulling on it will always
slow down and stop
An artificial satellite such as the International Space Station stays up because
the Earth curves out from under it as fast as it falls
In Newton's Theory of planetary motion,
the Sun and Earth move around each other
The force that acts on a rocket because its engine is firing is exerted by
the exhaust from the rocket
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
In the ancient Greek theory of gravity, everything was attracted to the center of the universe. In Newton's theory of gravity, everything was attracted
to every other object in the universe
When Newton calculated the magnitude and direction of the acceleration of Earth's Moon, he found that the direction was
toward the Earth
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
toward the Sun
The Law of Inertia says that if an object is not acted on by any outside force, its acceleration
will always be zero