Levers quiz #1 Flashcards
Levers quiz #1
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What are the three classes of levers in the human body, and how are their components (fulcrum, effort, load) arranged in each type?
The three classes of levers are: First class (effort-fulcrum-load), where the fulcrum is between the effort and the load; Second class (effort-load-fulcrum), where the load is between the effort and the fulcrum; and Third class (fulcrum-effort-load), where the effort is between the fulcrum and the load. How does the location of the fulcrum in a lever system affect mechanical advantage or disadvantage in body movements?
If the fulcrum is closer to the load, the lever provides a mechanical advantage, making movement easier. If the fulcrum is closer to the effort, the lever operates at a mechanical disadvantage, requiring more effort but allowing greater speed and range of motion. Why are third class levers, which operate at a mechanical disadvantage, so common in the human body, especially in the arms and legs?
Third class levers are common because, despite requiring more effort, they allow for greater speed and a larger range of motion. This enables rapid and extensive movements, such as throwing a baseball at high speeds, which is essential for many activities and sports. What are the three main components of a lever system in the human body?
The three main components are the rigid rod (bone), the fulcrum (joint), and the effort (force applied at the muscle insertion). How are the fulcrum, effort, and load arranged in a first class lever in the body?
In a first class lever, the arrangement is effort-fulcrum-load, with the fulcrum positioned between the effort and the load. Which type of lever in the body provides a mechanical advantage and is exemplified by the calf muscle lifting the heel?
The second class lever provides a mechanical advantage, as seen when the calf muscle lifts the heel with the load (body weight) between the effort and the fulcrum (toes). Why do third class levers, which operate at a mechanical disadvantage, allow for rapid and extensive movements?
Third class levers allow for greater speed and a larger range of motion, enabling fast movements like throwing a baseball, despite requiring more effort. How does the position of the fulcrum relative to the load and effort affect mechanical advantage in a lever system?
If the fulcrum is closer to the load, the system has a mechanical advantage; if it is closer to the effort, it creates a mechanical disadvantage. What is a classic example of a first class lever in the human body?
A classic example is the head pivoting on the neck, where the fulcrum is the joint, the effort is the muscle pulling, and the load is the weight of the head. Why are third class levers so common in the arms and legs despite their mechanical disadvantage?
They are common because they allow for rapid and extensive movements, which are essential for activities like throwing or running, even though they require more effort.
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