Chapter 2: Inertia (from Lecture Slide) Flashcards
Aristotle
One of the first pioneers to try to study and identify motion through classification
Two types of motion
Natural motion and violent motion
4 Greek States of Matter
Earth, water, air and fire (solid, liquid, gas and heat)
Natural Motion
1) Motion based on intrinsic properties of the object
2) Every object has a proper place and will strive to return to it
Unnatural (Violent) Motion
Produced by external pushes or pulls on objects (forces)
Summary of Aristotle on Motion
1) People followed his beliefs… for 2000 years
2) The normal (natural) state of objects is one of the rest
Through Earth must be in its proper place
A state of rest, and Earth must not move
Geocentrism
Universe with Earth at center, planets and Sun orbit Earth in perfect circle (church beliefs)
Heliocentrism (Heliocentric Model)
1) Sun-centered
2) All celestial bodies revolve around the sun
Published Work
1) On the Revolution of the Celestial Sphere
2) Heliocentric Theory
3) Alternative model to geocentrism
Problems with the Medieval Church
1) Fear of Prosecution
2) God put Earth at the center of the universe (supports geocentric model)
Italian Astronomer and Physicists
Followed Copernicus beliefs (Heliocentrism)
Disproved Aristotle on Geocentrism
Phase of Venus
Disproved Aristotle’s Falling Bodies Hypothesis with Leaning Tower Experiment
Objects of different weights fall at nearly the same rate
More problems with the church
1) Accused him of heresy
2) Ordered to be imprisoned and secluded
Venus phases prove it
Orbits the Sun
Galileo demolished Aristotle’s assertion in
The early 1500s
Galileo’s discovery object of
Different weights fall to the ground at the same time in the absence of air resistance
A moving object needs no force to keep it moving in
The absences of friction
Free fall and
Inertia
If there is no interference with a moving object, it will:
Keep moving in a straight line forever, no push, pull, or force of any kind is necessary
Galileo observed balls rolling down different curves
If smooth surface is used the ball got closer to its original height (Height at the starting point)
Galileo reasoned that the ball would get to
The original height if there were no friction
Slope downward
Speed increases
Slope upward
Speed decreases
No slope? Does speed change?
Neither
Downward slope, the object will
Pick up speed
Upward slope, the object will
Lose speed
A ball on a horizontal plane, it maintains
Its speed indefinitely
If the ball comes to rest, it is
Not
Weight does not affect
Speed of fall (with negligible air resistance)
In the absence of retarding forces (friction, drag, etc…) the tendency of an object is
To move forever without slowing down
The use of inclined planes for Galileo’s experiment helped him to
Discover the property called inertia
A force is
A push or a pull
Inertia
1) Property of matter to resist changes in motion
2) No force? moving objects will continue moving
3) Dependent on the amount of matter in an object (its mass)
Newton used Galileo’s observation to conclude that a force is
Not needed to keep an object in motion
Newton’s First Law of Motion
1) Invention of Calculus
2) Universal Gravitation
3) Theory of Color
4) Newton’s 3 Laws of Motion
An object at rest tends to stay
At rest
An object in motion tends to stay in motion with the same speed and in the same direction, unless:
Acted upon by an unbalanced external force
Every object continues in a state of rest or at uniform speed in a straight line unless
Acted on by a nonzero net force
An object continues to do whatever it happens to be doing unless
A force is exerted upon it
If it is at rest, it continues in
A state of rest
If an object is moving, it continues to move without
Turning or changing its speed
Newton’s First Law of Motion (Mass)
1) Quantity of matter
2) Measure of inertia
3) Not the same as weight
4) Measured in kilograms
More mass equal to
More inertia
More inertia equal to
More resistant to change its state of motion
Less mass equal to
Less inertia
Less inertia equal to
Less resistant to change its state of motion
Galileo’s absence of a force, which is mean?
Moving objects will continue moving
What is Newton’s refined from?
1) Galileo’s observation
2) First Law
Net forces and vectors changes in motion are produced by
A force or combination of forces
A Force is
A push or a pull
A force are included:
Gravitational, electric, magnetic, muscular effort
