1. Cornell Notes 2-4 What Are Graphs?
November 2, 2011
Page 67

2. Linear and Non-Linear Graphs
Linear graphs go in a straight line.
They represent relationships with the formula y=kx
k is the slope of the line. You can figure out slope by dividing change in y over change in x
(10-5)/(2-1)=5/1=5

3. Non-Linear Graphs Non-linear graphs go in curves
They usually have formulas like y=kx2

5. The Rectangle Method
You can use the rectangle method to make predictions.
Just find the key term on the axis, draw a straight line up to the graph, and another straight line to the other axis.
If you need to, you can extend the graph in either direction to help make your prediction

6. Position vs Time Graphs
In a position vs time graph, time is on the x and position on the y.
If the line is linear, then the object graphed I moving at a constant speed
If the line is non-linear, then the object’s speed is changing
For constant speed, objects with greater speeds have steeper slopes

7. Slopes on PvT Graphs
The slope on a PvT graph shows the speed of the object.
To calculate slope, do the following
Pick two points on the graph
Subtract the y-values of the points, the point on the right going first (y2-y1)
Subtract the x-values of the points, the point on the right going first (x2-x1)
Divide the y’s by the x’s (Rise over run)

8. Example (120 - 60)  (80 - 40) = 60  20 = 3 cm/s Y Goes Up 20
X Goes Up 40
( )  ( ) = 60  20 = 3 cm/s