1. U3d-L5
December 9, 2009
DRILL
Sketch the pictures below and answer the questions:
Which lever would be easier to push down, A or B?
Which load will travel the greater distance, A or B? A B

2. SIMPLE MACHINES LEVER INCLINED PLANE
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SIMPLE MACHINES
Principle: a law of nature underlying the working of an artificial device
Simple machines work on 2 basic principles:
LEVER
INCLINED PLANE

3. LEVERS Which class is the lever below? Describe it. SECOND CLASS
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LEVERS
Which class is the lever below?
Describe it.
THIRD CLASS
SECOND CLASS
FIRST CLASS

4. Examples? HOMEWORK REVIEW
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HOMEWORK REVIEW
With a new partner, go over your solutions to the homework.
Are the sketches accurate?
Is the class identification correct?
Examples?

5. PRINCIPLE OF THE LEVER WHEEL-and-AXLE A shaft attached to a disk
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PRINCIPLE OF THE LEVER
WHEEL-and-AXLE
A shaft attached to a disk

6. 2nd Class PRINCIPLE OF THE LEVER WHEEL-and-AXLE Which class of lever?
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PRINCIPLE OF THE LEVER
WHEEL-and-AXLE
Which class of lever?
2nd Class

7. 3rd Class PRINCIPLE OF THE LEVER WHEEL-and-AXLE Which class of lever?
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PRINCIPLE OF THE LEVER
WHEEL-and-AXLE
Which class of lever?
3rd Class

8. 1st Class PRINCIPLE OF THE LEVER PULLEYS
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PRINCIPLE OF THE LEVER
PULLEYS
Pulleys are grooved wheels attached to an axle.
Generally, what class lever do they act as?
1st Class

9. FORCE/DISTANCE MULTIPLIERS
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PRINCIPLE OF THE LEVER
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

10. FORCE/DISTANCE MULTIPLIERS
U3d-L5
PRINCIPLE OF THE LEVER
FORCE/DISTANCE MULTIPLIERS
From the drill:
Which is the force multiplier?
In other words, which arrangement gives you greater strength A B

11. FORCE/DISTANCE MULTIPLIERS
U3d-L5
PRINCIPLE OF THE LEVER
FORCE/DISTANCE MULTIPLIERS
From the drill:
Which is the distance multiplier?
In other words, which arrangement gives you greater distance A B

12. FORCE/DISTANCE MULTIPLIERS
U3d-L5
FORCE/DISTANCE MULTIPLIERS
Use the following information to determine the force required to lift the load using a 1st class lever.
L = 100 lbs.
Draw Sketches!
DL = 5 ft.
5 ft.
20 ft.
DF = 20 ft.
F = ????
F = ?
100 lbs.

13. FORCE/DISTANCE MULTIPLIERS
U3d-L5
FORCE/DISTANCE MULTIPLIERS
5 ft.
20 ft.
Write your equation
Substitute values
Solve for unknown
F = ?
100 lbs.
L x DL = F x DF
100 lbs x 5 ft = F x 20 ft
500 ft-lbs = F x 20 ft
20 ft ft
F = 25 lbs.

14. FORCE/DISTANCE MULTIPLIERS
U3d-L5
FORCE/DISTANCE MULTIPLIERS
Use the following information to determine the force required to lift the load using a 1st class lever.
L = 200 lbs.
DL = 10 ft.
10 ft.
20 ft.
DF = 20 ft.
F = ????
F = ?
200 lbs.

15. FORCE/DISTANCE MULTIPLIERS
U3d-L5
FORCE/DISTANCE MULTIPLIERS
Use the following information to determine the force required to lift the load using a 1st class lever.
L = 100 lbs.
DL = 20 ft.
20 ft.
20 ft.
DF = 20 ft.
F = ????
F = ?
100 lbs.

16. FORCE/DISTANCE MULTIPLIERS
U3d-L5
FORCE/DISTANCE MULTIPLIERS
Use the following information to determine the force required to lift the load using a 2nd class lever.
L = 100 lbs.
10 ft.
DL = 5 ft.
5 ft.
DF = 10 ft.
F = ????
F = ?
100 lbs.

17. FORCE/DISTANCE MULTIPLIERS
U3d-L5
FORCE/DISTANCE MULTIPLIERS
Write your equation
Substitute values
Solve for unknown
10 ft.
5 ft.
L x DL = F x DF
100 lbs x 5 ft = F x 10 ft
F = ?
100 lbs.
500 ft-lbs = F x 10 ft
10 ft ft
F = 50 lbs.

18. FORCE/DISTANCE MULTIPLIERS
U3d-L5
FORCE/DISTANCE MULTIPLIERS
Use the following information to determine the force required to lift the load using a 2nd class lever.
L = 200 lbs.
25 ft.
DL = 15 ft.
15 ft.
DF = 25 ft.
F = ????
F = ?
200 lbs.