Soc 20-levers Flashcards
What is a lever?
-‘lever’ refers to a system of muscles and bones working together to bring about movement
-when you exercise your muscles pull your bones, and your bones create movement,acting as levers
How does a lever work?
Fulcrum(or pivot)-the point around which the lever rotates(joints)
Load-the force that is applied by the lever system (resistance/object)
Effort-a force that is applied by the user of the lever system (muscles)
Lever arm- a rigid bar such as bone
What do each images represent
Fulcrum-triangle
Load-square
Effort-arrow
Lever arm- rectangle
Acronym
F-fulcrum
L-load
E-effort
First class lever-what is it?
Fulcrum is in the middle
Example 1-tricep dip
The elbow is the fulcrum which sits between the load (bodyweight) and the effort applied by the tricep
Example 2-nodding your head
The neck joint (atlas and axis) is the fulcrum which sits between the load (head) and the effort applied by the neck muscle
Second class lever-what is it?
The load sits in the middle between the fulcrum and effort
Example 1-calf raiser
The body weight (load) sits between the toes and balls of feet (fulcrum) and the gastrocnemius muscles apply the effort by pulling the heel
Example 2-lifting a wheelbarrow
The weight on the wheelbarrow when your carrying the load which sits between the wheel (fulcrum) and the handle (effort)
Third class levers-what is it?
The effort sits between the middle,between fulcrum and load
Example 1-bicep curl
The effort is applied by the bicep, which is between the fulcrum at the elbow jount and weight in your hands(load)
Example2-using a spade
The effort is applied by foot (gastrocnemius) which is between the fulcrum at the handle and weight on the soil (load)
Defenition of mechanical advanatges
A large load can be lifted with a relatively small amount of effect
This happens when the output lever is greater than input-the load is greater than effort, so you are getting more out than your putting in
Which levers are mechanical advanatges
First and second class levers