Levers Paper 2 Flashcards
What are the two functions of levers?
- To apply force (strength) to an object.
- To move the load a greater distance or through a greater range of movement.
What are the types of levers?
1st class levers 2nd class levers 3rd class levers
What is in the middle at a first class lever?
Fulcrum
What is in the middle at a second class lever?
Load
What is in the middle at third class levers?
Effort
Give an example of a first class lever in the body.
Dumbbell tricep extensions (elbow extension)
Give an example of a second class lever in the body.
Calf raises (plantar flexion at the ankle)
Give an example of a third class lever in the body.
Dumbbell curls (elbow flexion)
What are the two main benefits of levers?
- ) Large loads can be moved with a relatively small amount of effort.
- ) The distance a load can be moved, or the speed with which it can be moved, can be increased without an increase in effort.
What is a ‘load arm?’
The distance from the load to the fulcrum
What is an ‘effort arm?’
The distance from the effort to the fulcrum.
What is a mechanical advantage?
- When a lever’s effort arm is longer than it’s load arm. Levers with mechanical advantage can move large loads with less effort.
- 2nd class levers
Give an example of a second class lever with a mechanical advantage?
The take-off in long jump: The effort produced by the muscles, which is relatively small, is able to drive the full weight of the athlete off the ground.
What is a mechanical disadvantage?
When a lever’s load arm is longer than it’s effort arm. Whilst they are said to be a ‘disadvantage’, third class levers are able to increase the speed at the end of the lever arm.
Give an example of a third class lever with a mechanical disadvantage.
Hip joint: The hip joint is at a mechanical disadvantage as it has to apply a greater force to lift the load.
When is a first class lever at a mechanical advantage?
- When the fulcrum is closer to the load.
- A small amount of effort will result in more powerful movements of the load.
When is a first class lever at a mechanical disadvantage?
- When the fulcrum is closer to the effort.
- More effort is needed to move the load, but it can be moved at a higher speed.
What are the benefits of a first class lever?
Can increase both effort and the speed of a body.
What are the benefits of second class levers?
Tend only to increase the effect of the effort force.
What are the benefits of third class levers?
Can be used to increase the speed of a body.
Shoulder, elbow, hip and knee joints are…
3rd class levers
An ankle joint is a….
2nd class lever
Extension of the elbow joint only is a…..
1st class lever
