Untitled Flashcards Set

They use simplified models to better understand the world and they use mathmatics to analyze and sumarize there observation and they us emathmatical relation ships between physical quantities to predict what will happen in new sitiauations

Tables and graphs and equations can help make them easier

What was galilos hypothesis? 

He dropped  a table tennis ball and a golf ball into a vacum and measured how far a ball falls in a certain time travel

They use numbers on how much distance in takes in how much time

The more time is used the higher the amount of distance that was taken

We can analyze data by using a graph as well  of the distance the ball drops in each time travel it can give us an obvious patren  we can draw a smooth line  to make estimations for times we have no data

The shape of the graph can also give us  the relationship between m and s

We have an equation that can help us to reproduce a graph and change in position  for any aribtary time during the fall its

Delta y = 4.9 x changes of times in seconds delta t ^ 2

Its basically change of fall in meters = 4.9 x time of fall in second  ^ 2

Physics equations indicate relationships

Smathmatics uses equations to determine relationship between variables physics uses tools of mathmatics to describe measured or predicted relaationships betweenphysical quantities in a situation

The physical equation is a compact statement that explains our models

 one or more variables may effect the answer of an expirement

Many of the important physics equation don’t contain numbers

Instead the represent a simple discription between related physical quantities

The letter v is used to express as speed  sometimes greek letters are used such as delta change of something and sigma tha sum or total 

Delta y describes the change of the balls position and delta t describes the elapsed time (  time changes it self)

Abbreviations for variables and units ( shortened word )

Change in position Delta x and y its unit is meters

Time interval Delta t its unit is seconds

Mass m kilograms

Dimensional analysis

Makes ues of the fact that dimensions can be treated as algebraic expressions

Using dimensions to make a simple physical equation or check its valid

Quantities can be added or subtracted ONLY of they have the same dimension

For example for the car example its goes 725 km and its 88km an hour

Its speed length/t x length

88km/h x 725

But it isnt for time

For time we have to divide distance by the speed of the car

725km x 1 hour / 88km

It can be usefull estimating a problem rather than directly solving it with very big numbers its called order of magnitude

The nearest power of 10 value to the value of physical quantity

Determining the power of 10 that is closer to its true numirical value of that quantity

For example 10 ^3 its for 725 but 10^2 its for 88

We can even use order of magnitude in situaiation when littile information is given

5mil people  5 people = a car  its 1000000 cars  each car travels about

30000 km or 10000km er a year so we will use 20000

100km - 20 g

So 20000 km x 20 devided by 100 is 4000

So we have 4k multiple b1 million

In decimals we count number one aswell

But in not decimals we only count zeros