Levers Flashcards
Axis
An imaginary straight line around which a body or object rotates.
Fulcrum
The point which the lever rotates.
Load
The force that is applied by the lever system.
Effort
The force that is applied by the user of the lever system.
F.L.E
First Class Levers - Fulcrum in the middle.
Second Class Levers - Load in the middle.
Third Class Levers - Effort in the middle.
First Class Levers
Left On Top - Effort (Posterior Muscles connected to the neck)
Middle Bottom - Fulcrum (Neck Joint)
Right Top - Load (Head)
Second Class Levers
Left Bottom - Fulcrum (Toes)
Middle Top - Load (Body)
Right Top - Effort (Calf Muscles)
Third Class Levers
Left Bottom - Fulcrum (Elbow Joint)
Middle Top - Effort (Bicep Muscles)
Right Top - Load (Forearm)
Advantages of a First Class Lever System
- Strong
- Stable
- Increasing the length of the lever will increase the mechanical advantage.
Advantages of a Second Class Lever System
- Strong
- Stable
- Increasing the length of the lever arm will increase the mechanical advantage.
Advantages of a Third Class Lever System
- Large range of motion.
- Movement is fast.
- Increase the length of the lever will decrease the mechanical advantage.
Disadvantages of a First Class Lever System
- Slow acting movement.
- Limited flexibility.
Disadvantages of a Second Class Lever System
- Slow acting movement.
- Limited flexibility.
Disadvantages of a Third Class Lever System
- The amount of force applied must always exceed the weight of the load.