The mathematical relationship is 1 𝐸 =𝑘 𝐹   Where k = the gradient of the line The mathematical relationship is 𝐸=𝑘 1 𝐹

C = k 𝑫 C2 = k D

P = I2R Example: Power / Current graph:

y is proportional to x2 Sketch A vs B Replace A with A2 1 3 4 12 9 27 16 48 25 75 36 108 A B 1 3 2 12 27 4 48 5 75 6 108 Sketch A vs B Replace A with A2 Now plot B versus A2, you should now have a straight line through the origin Find the gradient of this line: Apply y= mx + b analysis to determine the relationship equation

y is inversely proportional to x

Sample Problem: Sketch V vs P Replace V with 1/V Now plot 1/V versus A V(m3) P(Pa) 3.0 1 1.5 2 1.0 3 0.75 4 0.6 5 0.5 6 Sketch V vs P Replace V with 1/V Now plot 1/V versus A If your guess was right you should now have a straight line through the origin Find the gradient of this line Apply y= mx + b analysis to determine the relationship equation

You could use your graphing calculator

Or USE a Spreadsheet