Trivia
What was the title of Copernicus' book?
De Revolutionibus
A ball is rolled across a counter top and rolls slowly to a stop. How would Aristotle interpret this behavior? How would Galileo interpret it? How would you interpret it?
Aristotle would say, the ball stopped when it reached it natural position, Galileo would say, friction overcame the ball's natural tendency to continue rolling; you would agree with Galileo.
How does the law of inertia apply to objects in motion?
The law of inertia states that objects in motion remain in motion.
How can you express the equilibrium rule mathematically?
ΣF = 0
Which of the following is the best statement of Newton's first law of motion?
Objects at rest stay at rest, objects in motion stay in motion in a straight line at constant speed, unless compelled to change that state by forces exerted upon it.
Where was Galileo from?
Italy
An airplane flies horizontally at constant speed in a straight-line direction. Its state of motion is unchanging. In other words, it is in equilibrium. Two horizontal forces act on the plane. One is the thrust of the propeller that pulls it forward. The other is the force of air resistance (air friction) that acts in the opposite direction. Which force is greater?
The thrust of the propeller is greater.
Two thousand years ago, people thought that Earth did not move. One major reason for thinking this was that
Earth was near the center of the universe.
A force of gravity between the sun and its planets holds the planets in orbit around the sun. If that force of gravity suddenly disappeared, in what kind of path would the planets move?
Each planet would move in a spiral path away from the sun at a decreasing speed.
According to Galileo, when is a force needed to keep an object moving?
When it is moving away from it's natural position
Which law states that every object continues in a state of rest, unless acted on by a nonzero net force?
Newton's First Law
or
Law of Inertia
When a 110-pound person stands on two bathroom scales with their weight evenly distributed between the two scales. What is the reading on each of the scales?
0-pounds and 0-pounds
Does a 2-kilogram bunch of bananas have twice as much inertia as a 1-kilogram loaf of bread?
Yes
What is the relationship between mass and inertia?
The more mass an object has, the greater its inertia and therefore the more force it takes to change its state of motion.
What did Copernicus state about Earth's motion?
That the Earth moves around the Sun.
If gravity between the sun and Earth suddenly vanished, Earth would continue moving in a(n)
straight-line path.
Two sets of swings are shown. If the children on the swings are of equal weights, the ropes of which swing are more likely to break?
The ropes on the right
Galileo’s conclusions about motion helped advance science because they were based on
philosophical discussions rather than experiments.
To say that 1 kg of matter weighs 10 N is to say that 1 kg of matter
has ten times more inertia than 10 kg of matter.
According to Aristotle, what were the two types of motion?
Violent and Natural
When was Nicolaus Copernicus born?
(1473–1543)
The Earth moves about 30 km/s relative to the sun. But when you jump upward in front of a wall, the wall doesn’t slam into you at 30 km/s. A good explanation for why it doesn’t is that
the sun’s influence on you is negligible.
If you apply a Net force to an object
you may change the motion of the object.
How can you find the resultant of two vectors?
To find the resultant of two vectors, construct a triangle wherein the two vectors are adjacent sides. The diagonal of the triangle shows the resultant.
According to Aristotle and his followers over centuries, Earth was at the center of the universe. The first European to effectively challenge that notion was
Copernicus.