Levers Flashcards
What are the different parts of a lever system?
Lever
Fulcrum
Effort
Load
What acts as a lever in the body?
Bones
What acts as a fulcrum in the body?
Joints
What acts as the effort in the body?
Muscles
What acts as a load in the body?
Body weight / weight of limb / weight of something they are holding
What are the 3 classes of lever?
1st class, 2nd class, 3rd class
Draw a 1st class lever
Draw a 2nd class lever
Draw a 3rd class lever
Give a detailed example of two first class levels in the body?
Extension of the neck when preparing to head a ball in football
Fulcrum=neck, effort=trapezius, load=cranium
Extension of the elbow during a bicep curl
Fulcrum=elbow, effort=biceps brachii, load=forearm/weight in hand
Give a detailed example of a 2nd class lever in the body
Plantarfelxion of the ankle when taking off in high jump
Fulcrum=ankle, effort=gastrocnemius, load=bodyweight
Give a detailed example of two third class levers in the body
Upwards phase of a bicep curl
Fulcrum=elbow, effort= biceps brachii, load=forearm/weight in hand
Extension of knee when kicking a football
Fulcrum=knee, effort=quadriceps, load=lower leg
What does the term ‘effort arm’ mean?
The distance between the effort and the fulcrum
What does the term ‘load arm’ mean?
The distance between the load and the fulcrum
What is meant by a mechanical advantage?
A large load can be moved with a relatively small effort
Which class of lever always has a mechanical advantage?
A 2nd class lever system always has a mechanical advantage as the effort arm is always greater than the load arm
What is meant by a mechanical disadvantage?
A large effort is required to move a relatively small load
Which class lever always has mechanical disadvantage?
A 3rd class level system will always have mechanical disadvantage as the load arm is always bigger than the effort arm
What is the advantage of having a third class level?
A 3rd class level can move a load at a high velocity over a large range of movement.
