Soc 20- Lever Systems Flashcards
What are the three types of levers?
First class levers
Second class levers
Third class levers
Fulcrum
The point around which the lever rotates
Load
The force that is applied by the lever system (e.g dumbbell)
Effort
A force that is applied by the user of the Lever System (supplied by muscles)
First class lever
Fulcrum is in the middle
Second class lever
Load is in the middle
Third class lever
Effort is in the middle
Lever arm
A rigid bar such as a bone
What is a lever?
In your body the term lever refers to a system of muscles and bones working together to bring about movement.
Lever system in the body (exercise)
When you exercise your muscles pull on your bones and your bones create movement acting as levers
First class lever system exercise
Tricep dip
First class lever system example
Heading in football
Neck muscles provide effort
Head + ball (load)
Top of your spine (fulcrum)
Second class lever system exercise / example
A calf raise
Body weight - load
Ball of your feet (fulcrum)
Gastrocnemius (effort)
Which lever system is most common?
Third class lever system
Third class lever system example / exercise
Dumbbell bicep curl
Effort - biceps
Fulcrum - elbow
Load - dumbbell
Calculating Mechanical advantage
Divide the input by the output
When does a mechanical advantage happen?
When the output of the lever is greater than the input
When the load is greater than the effort
Which lever systems work at a mechanical advantage?
First and second class levers
When does a mechanical disadvantage happen?
When the effort and the load are both the same side of the fulcrum but the effort sits closer to the fulcrum than the load does.
Which lever systems work at a mechanical disadvantage?
Third class levers
