Unit 2: Graphical Relationships

Sprayberry

Physics

Physics Comp BookUNIT 2: Graphical RelationshipsCopy GPS listed on the LTA. Circle the verbs; underline the

nouns. Page Contents 10 Concept Map: Graphical Relationships 11 independent variable / dependent variable 12 x-axis, y-axis 13 slope / 14 Example: Translating Graphs 15 Lab SUMUPS:

* Moving Man Internet Lab* Running Man

p. 9

Concept Map: Graphical Relationships

GraphingBasics Slope

on position vs. time

on velocity vs. time

on acceleration vs. time

= velocity!

= acceleration!

= zero(in our class)

•X-axis

•Y-axis

•independent & dependent variables

•Reading graphs

RiseRun

Graphing Basics: Labeling the axes

Scientists have rules for choosing which variable is graphed on which axis.

On the X-axis (horizontal) is the independent variable

On the Y-axis (vertical) is the dependent variable

Which is the x-axis and which is y-axis?

Graphing Basics:indep vs. dep variables So what are the independent

variable and dependent variables?

The independent variable is not affected by the changing dependent variable.

The dependent variable changes as the independent variable.

In other words, the dependent variable DEPENDS on the independent variable.

Independent or dependent? Time vs. position Time vs. velocity Time vs. acceleration

Where would these go on the graph?

Graphing Basics: more on variables…

Time (as in a particular moment in time) is TYPICALLY the INDEPENDENT variable.

In this class, if time is graphed, it is on the x-axis.

Think about it: nothing stops time.

Time doesn’t change with speed; speed changes with time.

Independent or dependent? Time vs. position Time vs. velocity Time vs. acceleration

Where would these go on the graph?

Frayer Models for: x, y axis & independent and dependent variables

Definition:

Examples:How to remember:

Picture:

Graphing Basics: Slope

The slope of a line describes its steepness. It is the ratio of the vertical change (called the rise) to the horizontal change (called the run).

slope = rise vertical change run horizontal change

Let’s look at the slope of this line: We can use any two points on the

line (the slope of a line is constant). What is the rise? What is the run?

Finding slope --practice

Another example: Find the slope— slope = rise vertical change

run horizontal change

GRAPHING MOTIONUse a DISTANCE/TIME GRAPH

-Time = X axis

-Distance = Y axis

A graph of constant speed will represent the motion with a straight

lineTo show two constant speeds which are

different, you use SLOPE = steepness of the line =

speed

Steeper the slope = faster the speed

Constant Versus Changing Speed

time

spee

d

time

spee

dCONSTANT SPEED CHANGING SPEED

GRAPHING MOTION

A graph of changing speed will have a zig-zag or curved line

Putting it all together

TIME

DIS

TA

NC

E

FASTEST CONSTANT SPEED

SLOWER CONSTANT SPEED

CHANGING SPEED

What is the slope of this part of the line?

Putting it all together

10 20 300

200

600

1000

What is the average speed (slope) during the 10 min to 20 min period?

Change in distance = 1200-600 = 600m

Amount of time = 20-10 = 10 min

Avg. Speed = change in distance (600 m)

Amount of time (10 min)= 60 m/min

Frayer for Slope

Definition:

How to calculate:

Picture:

What to remember:

What does slope mean?