Conservation of Momentum

-The Law of Conservation of Momentum states tha the total momentum of any group of objects that interact do not change.

-When two objects collide in the absence of fricton, momentum is not lost.

Do Action-Reaction Forces Cancel?

*Newtons Law refers to individual forces and their opposites. That is why it is possible for two skaters to push off of each other and not end up the same distance from their starting point.*

.If one skater had more mass than the other, it would take more force to puch them and they wouldn't travel as far.

Newton's Third Law of Motion

-When one object exerts a force on a second object exerts an equal but opposte force on the force.

.forces are equal and oppposite but act on different objects.

.they are not "balenced forces"

ex).the movement of the horse depends on the forces acting on the force

ACTION-REACTION PAIRS

-The rocket exerts a downward force on the exhaust gases.

-The gases exert an equal but opposite upward force on the rocket.

-both objects accelerate

-The amount of acceleration depends on the mass of the object

A Projectile Motion

-Projectile

.any object thrown in the air

.acted upon only gravity

.follow a path called a trajectory

-Centripetal Acceleration

.acceleration toward the center of a circular path

.caused by centripetal force

-On the ground...

.friction provides centripetal force

-In orbit...

.gravity provides centripetal force

-Free Fall

.when an object is influenced only by the force of gravity

-Weighlessness

.sensation produced when an object and its surroundings are in free-fall.

.object is not weightless!

.surroundings are falling at the same rate so they dont exert a force on the object.

Air Resistance

-Terminal Velocity

.maximum velocity reached by a falling object

-No net force

.no acceleration

.constant velocity

-Falling wth air resistance

.heavier objects fall faster because they accelerate to higher speeds before reaching terminal velocity

-Larger Force gravity

.need larger force of air

.need higher speed

FORMULAS:

for finding the:

-force~F=ma

-mass~M=f/a

-acceleration~A=f/m

F=ma

Force=Newtons-kg x m/s [squared]

Mass=kilograms

Acceleration=m/s [squared] (9.8 m/s [squared])

Chapter 3: Motion and Forces

Section 1-

Reference Point-Lets you know an object is in motion by comparing it to another point.

-Speed-The rate of change in position.
-Instantaneous Speed-is the rate of motion at any given instant (just like a picture)
-Contant Speed-A speed that does not vary.
-Average Speed- Is the total distance traveled divided by the total time of travel. (distance/time)
----------------------------------------------------

Speed & Velocity

-velocity
.speed in a given direction
.can change even when speed is constant

Acceleration
.the rate of change in velocity
.change in speed or direction
(slowing down-negative acceleration)

a=
vf-vi
t
a=acceleration
vf=final velocity (end)
vi=initial velocity (start)
t=time
---------------------------------------------------

Graphing Motion

Distance-Time Graph
x axis=Time
y axis=Distance

.slope=speed
.steeper slope=faster speed
.straight line=constant speed
.flat line=no motion

Distance-Speed Graph
x axis=Time
y axis=Speed

.slope=acceleration
.straight line=constant acceleration
.flat line=constant velocity
--------------------------------------------------------

NEWTON'S FIRST LAW OF MOTION

.An object will not change its motion unless a force acts on it.
.An object that is not moving remains at rest until something pushes or pulls it.
.An object that is moving remains moving until something pushes or pulls it.
.The force that causes objects to slow down is friction.
.Friction always acts opposite to the direction of motion.
.To keep an object moving when friction is acting on it, you have to keep pushing or pulling on the object to overcome the frictional force.
.All objects resist having their motion changed.
.This tendancy to resist a change in motion is called inertia.
.The more mass an object has, the greater its inertia.
-----------------------------------------

Force

-Force
.a push or pull that one body exerts on another.
-Balanced Forces
.forces acting on an object that are opposite in direction and equal in size.
.no change in velocity
-Net Force
.unbalanced forces that are not opposite and equal.
.velocity changes(object accelerates)
----------------------------------

Gravity

.a force that pulls bodies of mass together.
-Weight
.A planet's gravitational pull on an object. This give the object weight.
-Mass

.the amount of matter that an object contains.

.Gravity&& the Scale
.Gravity pulls an object down and a scale measures the pull.
.Earth keeps us on the ground
.Earth's gravity pulls us toward the center of the planet
.Things with mass
.Planets, stars, moons
.Weigh less on moon?
.moon has less mass, less gravity-less pull, less weight
*anything that has [mass], has [gravity]

Chapter 2: Measurement

Conversions

Kilo-1000

Hecto-100

Deka-10

Base Unit

Deci-.1

Cent-.01

Milli-.001

Mnumonic

K-evin

H-elped

D-an

O-n

D-ifferent

C-ommon

M-easurements

-Larger Unit-decimal point-LEFT

-Smaller Unit-decimal point-RIGHT

Graphing (pg. 48-51)

.Types of graphs
.Graphing & Density

-Line Graph
.shows the relationship between 2 variables
Dependant(y axis)temperature
&
Independant(x axis)Time

-Bar Graph
.shows information collected by counting
Dependanthow many
IndependantTemperature

-Pie Graph
.shows distribution of parts within a whole quantity
(no more than 6 sections)

Chapter 1: The Nature of Science

Defining Science

Problem Solving

Scientific Method

Experimental Design

Defining Science

-Pure Science

.Research that adds to the body of scientific knowledge

.has no practical use

-Applied Science (Technology)

.the practical application of scientific knowledge

Pure

.human genetics

.polymer science

.atomic theory

.study of the human ear

Applied

.DNA fingerprinting

.Lycra spandex
.nuclear weapons

.hearing aids

-Life Science

.the study of living organisms

-Earth Science

.the study of Earth and Space

-Physical Science

.the study of matter and energy

.chemistry & physics

Problem Solving

1) Identify the problem

.What do you know?

.What do you need to know?

2)Plan a strategy

.Look for Patterns

.Break the problem into small steps

.Develop a model

3)Execute you plan

4)Evaluate your results

.Did you solve the problem?

.Is your answer reasonable?

Identify,Plan,Execute,Evaluate (IPEE)

Scientific Method

-Hypothesis::testable prediction

-Theory::explaination of "why"

.based on many observations + experimental results

-Scientific Law::predicion of "what"

describes a pattern in nature

Theories and laws are well-accepted by scientists, but...

THEY ARE NOT SET AND STONE

They are revised when new information is discovered

1)Determine the problem.

2)Make a hypothesis.

3)Test your hypothesis.

4)Analyze your results.

5)Draw conclusions.

Experimental Design

-Experiment::organized procedure for testing a hypothesis.

-Key Components:

.Control-standard for comparison

.Single Variable-keep other factors constant

-Types of Variables:

.Indepentant Variable

-adjusted by the experimenter

-what you vary

.Dependant Variable

-changes i response to the independant variable

-what you measure

Are Viruses Living or Not???

The Virus

What is a virus?
Do you think it's living or nonliving?
Why?

The picture on the left just so happens to be a virus (which everyone is 7-1 should know by now). A virus is a small particle that needs a host cell to live in and reproduce. To answer the question if it is living or not. I would say no, I do not think it is living.

In our notes it said:

Not Considered Living
.a virus is not a bacteria, fungus, protist, plant or animal.
.they cannot carry out cellular functions
.A virus can not replicate without infecting cells and then using the organelles an enzymes of the cells of the host.

I think it is not living because WAY in the beginning of the year, we were talking about characteristics of living things.

Our notes then said:

Characteristics of Living Things
-Living things move, use energy, grow and develop, respond to a simulus, and reproduce.

Although a virus can reproduce and move, it still can not use energy, grow and develop, or resong to a simulus, or im pretty sure they dont. ?:(.

That is why I think that viruses are not living.

Classifing Organisms

The real question here is::How do we know if scientists will or will not be able to classify all organisms?" In the article we read it said that scientist will try to classify all organisms in 25 years...a huh...i would most definitly want to see that happen...but unfourtunatly that wont happen...like i said before, most organisms are going extinct. Scientists are going WAY ahead of themselves. Even though they have a good advancment in technology it doesnt mean they WILL be able to classify ALL organisms. But you never know, it could (with a greater advancement in technology) or it could not. The point is that no body really does know if scientist will classify all organisms because we dont know what will happen in the future. But scientists are trying to discover and classify all organisms as fast as they can.

Another Question is:: Why do we classify organisms?
There is such a diversity of life on Earth that scientists developed a system that names living things and organizes them into groups. You all might already know this. But this is a reminder...if you get stuck with notes or something:: The groups are; Kingdom, Phylum, Class, Order, Family, Genus, and Species. And the naming system that gives humans first and last names is called binomial nomenclature. The point here is that we classify organisms because there is too many of them. Like say if you have a bunch of different papers...homework, tests, notes, and fliers...they are all in one folder...then all of a sudden u cant find your homework...what would you do? Organize them right? That way you know where everyhing is...The same with organizing organisms. There is sooo many different organisms you have to classify them, so you know where it fits in your folder.haha. Thats why we classify organisms.

The rush to classify organisms

The importance of rushing to classify all the organisms is because most species are going extinct. If they go extinct then there will be a very slim chance that scientists will not be able to classify them because...well...organisms won't be around for scientists to classify them.