# SC 100

### 34 terms by startas

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Chapters 1-5

### Scientific Method

- Gather Data, find patterns, make a hypothesis, make a prediction, gather data again.

### Gathering Data

Observation & Experimentation (placebo, control group, blind/double blind)

### Placebo

Testing new medicine - sugar pill - psychological impact - neither group knows if you're getting medication. *measure both groups

### Blind/Double Blind

Person giving medication doesn't know what pill is which, so they don't act differently when administering the medication

Yes

### Hypothesis

A tentative explanation of some regularity of nature, based on patterns in data.

### Theory

A thoroughly tested explanation of basic natural phenomena.

### Law of Nature

A concise statement or mathematical equation about a fundamental relationship or regularity of nature.

### A hypothesis is...

A tentative explanation for a natural phenomenon

### Prediction

A statement, made in advance, about what one believe will happen or how a particular system will behave - in the scientific method - the prediction is based on the hypothesis

### The scientific method, which is very useful in many fields besides science, is simply...

A systematic way of evaluating evidence

### Pseudosceience

Use of vague, exaggerated or untestable claims, or untestable claims

### Mechanics is concerned with:

The behavior of physical bodies when forces act on them. The effect of moving bodies on their environment.

### The Universe

regular and predictable, the universe is not random. It moves in regular, predictable ways.

### Planetary Motion:

Ptolemy - geocentric model of universe, copernicus - heliocentric model of universe, Kepler and Brahe - elliptical orbits

### Ptolemaic and Copernicus systems assumed?

All orbits are circular

### Mechanics

Branch of physics that deals with the motion and the forces that act on them

### Kinematics

The description of motion - Galileo

### Dynamics

The explanation of motion - Newton

### Speed

the distance an object travels per unit time: s=d/t

### Velocity

speed with a direction

### Acceleration

the change in velocity of an object per unit time - a=v2-v1/t2-t1

### Uniform motion

no change in speed or direction

### Acceleration

a change in speed or direction - that is, a change in velocity

### Galileo's experiments showed?

All objects fall at the same rate regardless of their mass and the velocity of a falling object that starts from rest is proportional to the length of time that it has been falling: v(m/s)=a(m/s2)xt(s)

### Distance is proportional to:

the square of the time traveled d=1/2xaxt2

g=9.8m/s2

planetary motion

### Galileo described

motion of falling objects

why things move

### Newtons 1st law of Motion:

every object continues in its state of rest, or in uniform motion, unless it is compelled to change that state by forces impressed upon it.

### The greater the force,

the greater the acceleration. a=f/m or f=m*a

### Newton's 2nd law of Motion:

The acceleration produced on a body by a force is proportional to the magnitude of the force and inversely proportional to the mass of the object

### Newton's 3rd law of Motion:

between any two objects, there is an attractive force proportional to the product of the two masses divided by the square of the distance between them f=gm1m2-d2

Example: