Physics: Chapter 3 Notes
Chapter Three: Newton's First Law of Motion
Terms in this set (37)
What cause changes in motion?
Who was Aristotle? What did he study?
-studied motion, and divided it into two types
What are the 2 types of motion according to Aristotle?
What is Natural Motion?
-was thought of to be either straight up or down
-it is something wanting to find its natural resting place
-Ex: heavy things fall, light things float
What is Violent Motion?
-was imposed motion
-result of forces that pushed or pulled
-there is an external cause
-imparted to objects
-objects in their natural resting place couldn't move themselves
For almost 2000 years, it was thought that a force was responsible for an object moving..?
-against its nature
Who was Nicolaus Copernicus?
-reasoned the simplest way to interpret astronomical observations was to assume that the earth and other planets went around the sun
-while everyone else thought geocentrically
What is Geocentric?
Geocentric is the belief that all the planets circle around the earth-- ERRR!
Who was Galileo?
-Galileo argued that only when friction is present, a force is needed to keep an object moving
-of the late renaissance era
What was Galileo's great contribution?
demolishing the notion that force is necessary to keep an object moving
What is friction?
-force that acts between materials that touch as they pass each other
--caused by irregularities in the surfaces of all objects
What would happen if friction was absent?
-a moving object would need no force what-so-ever to remain in motion
-ex: a ball would continue to roll horizontally in a straight line
Who said what wold happen if the friction was absent?
What is the tendency of a moving object?
-to continue moving
-to resist change to its state of motion
What is inertia?
the property of a body to resist changes to its state of motion
What is Newtons Law of Inertia?
-says every object in a state of rest, stays in a state of rest, or of uniform speed in a straight line, unless acted on by a non-zero net force
What does the Law of Inertia provide?
-different way of viewing motion from ancients
--objects continue to move by themselves
--forces needed to overcome friction
What is the relation of Inertia and Mass?
-the more mass an object has, the greater its inertia
What is the relation of force and mass and Inertia?
-The more mass an object has, the greater its inertia, and the more force it takes to change its state of motion.
How do you describe mass?
-roughly the amount of material present in an object
-measured in kilograms, etc.
-mass is more fundamental than weight
-mass is measure of amount of material IN an object
-amount of matter is measuring gravitational attraction to earth
Are mass and volume the same?
How do you describe volume?
-is the measure of space, and is measured in units such as cubic
Are mass and weight the same thing?
How do you describe weight?
-measure of gravitational force acting upon the object
What is Inertia?
-an objects tendency to stay at rest
Is mass= inertia?
Yes! If you had a stone, the amount of material in the stone is the same whether the stone is located on the earth, moon, or in outer space.
Mass is NOT changing depending on its location..
same force required to shake the stone with the same rhythm no matter where its located.
Mass is the quantity..
of matter in an object, measure of inertia
Weight is the..
weight is the force of gravity on an object
Mass and weight are..
proportional to each other in a given place (when one changes, the other changes)
In the same location.. twice the mass weighs..
twice as much!
-they are proportional to each other, but NOT equal!
-common to describe the amount of matter in object by gravitational pull
--in the USA we use mass, and kilograms
One Kilogram= 2.2 Pounds
-SI Unit of force is netwon
--the symbol is 'N'
-one newton is slightly less than quarter of a pound
10 Newton= 1 Kilogram= 2.2 Pounds
The Law of Inertia states that objects in motion..
remain in motion if no unbalanced forces act on them
-objects move WITH earth!
Once an object is in motion..
it stays in motion! (Inertia says this)
Law of Inertia applies to
state of motion because EVERYTHING is moving!