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)
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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
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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
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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.
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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)
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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