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
Mechanical disadvanatges defenition
Definition: Third class levers cannot lift as heavy a load
with the same amount of effort, due to the position of
the effort and load from the fulcrum.
This happens 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.
The input of the lever is greater than the output - the
force you apply is greater than the load so you are
putting in more than you are getting out.
Which levers are mechanical disadavntages
Third class levers
