Grade 8 Science - Balancing Lever Review Notes and Link to Assignment

https://www.dropbox.com/s/9y7z4k43hfmgdji/Grade%208%20Science%20and%20Technology%20Unit%203%20Lever%20Worksheet.pdf

To find the distance to balance objects, you have to use the work formula (w=fd) for each side of the fulcrum. Start by calculating the work/energy for the side where you know both the force and the distance. When the lever is balanced, the work on one side equals the work on the other side for the fulcrum. That means you can use the same value for work and reapply the formula on the other side, knowing either force or distance, to solve for the value you don't know.

F = 10N                                           F= 2N
D = 4m                                            D= ?m
___x________________________x___
                    ^

W(left)=fd
= (10)(4)
= 40J

W(left)=W(right)

W(right)=fd
40 = (2)d
40/2 = d
d= 20m


This is the applied in a similar context when using class two and three levers. The difference is the W(left)=W(right) is replaced by the idea W(input or effort) = W(load), where the d(distance) is always the distance from the input force/effort applied to the fulcrum, or the load to the fulcrum.