1. February 27, 2008
DRILL
Use the following information to determine the force required to lift the load using a 1st class lever.
What would DF have to be to make the applied force half of what it was for #1 above?
What is the mechanical advantage of a movable pulley system? How much F to lift L = 100 lbs?
L = 100 lbs.
F = ?
DL = 40 ft.
DF = 40 ft.
F = ????

2. FORCE/DISTANCE MULTIPLIERS
U3d-L13
FORCE/DISTANCE MULTIPLIERS
Sketch a picture
Write your equation
Substitute values
Solve for unknown
What can you say about the relationship between the Force, Load, DF, and DL by this problem?
40 ft.
40 ft.
F = ?
200 lbs.
L x DL = F x DF
100 lbs x 40 ft = F x 40 ft
4000 ft-lbs = F x 40 ft
40 ft ft
F = 100 lbs.

3. FORCE/DISTANCE MULTIPLIERS
U3d-L13
FORCE/DISTANCE MULTIPLIERS
What would DF have to be to make the applied force half of what it was for #1 above?
What can you say about the relationship between the Force, Load, DF, and DL by this problem?
40 ft.
DF = ?
L x DL = F x DF
100 lbs x 40 ft = 50 lbs x DF
F = 100 lbs.
4000 ft-lbs = 50 lbs. x DF
200 lbs.
50 lbs lbs
DF = 80 ft.

4. PRINCIPLE OF THE LEVER PULLEY
U3d-L13
PRINCIPLE OF THE LEVER
PULLEY
Movable Pulley – splits the work in half.
How many strands are supporting the load?
What is the MA of a movable pulley?
How many lbs of force are required to lift 100 lbs of load?
When a movable pulley is used, the force needed to lift a load is half that of the load. 2 2 50

5. Lever problems, Pulley problems
U3d-L13
QUIZ MONDAY
Lever problems, Pulley problems
Mechanical Advantage – MA = DF/DL = L/F
Steps of Engineering Design Process – Know the order of steps and the results of each step

6. FORCE/DISTANCE MULTIPLIERS
U3d-L13
FORCE/DISTANCE MULTIPLIERS
Simple Machines can be:
Force Multiplier: Increases the force applied to the work at hand
Distance Multiplier: Increases the distance the load moves
MECHANICAL ADVANTAGE
MA is the number of times a mechanical device multiplies the Applied Force

7. Final Design Report due Monday 3/3
U3d-L13
Final Design Report due Monday 3/3
Requirements:
Rewrite all steps to include required information as well as rubric guidelines.
You must include your previously graded steps with the grade on them (steps 1-6).
Part of your grade will be your improvement since the first grading.
Quiz Monday on the steps of the Engineering Design Process – know the order of the steps and what is required for each step

8. USE STEP GUIDELINES YOU SHOULD NOW HAVE IN YOUR NOTES
U3d-L13
USE THE RUBRIC!
USE STEP GUIDELINES YOU SHOULD NOW HAVE IN YOUR NOTES

9. U3d-L13
Class Competition