Chapter 11: The Lever System and Leverage Flashcards
What is the rigid structure that moves around a fixed point in a lever system?
The lever
What is the fixed point called around which a lever moves in a lever system?
Fulcrum
What is the force that causes movement in a lever system?
Effort
What is the force exerted by muscular contraction?
Effort
What is the force that opposes body movement?
Load/Resistance
What might the load consist of?
a) the body part you are trying to move
b) the resistance that the body part is trying to overcome
What determines whether a lever operates at a mechanical disadvantage or a mechanical advantage?
The relative distance between the fulcrum and the load and the point at which the effort is applied.
When the load is closer to the fulcrum, the lever is at a mechanical _____
advantage
When the effort is farther from the fulcrum, the lever is at a mechanical _____
advantage
When the effort is closer to the fulcrum, the lever is at a mechanical _____
disadvantage
When the load is farther from the fulcrum, the lever is at a mechanical _____
disadvantage
Chewing with your back teeth is an example of a mechanical ____, whereas chewing with your front teeth is an example of a mechanical _____
a) disadvantage
b) advantage
In a mechanical ____, a small effort moves a large load over a ____ distance
advantage
small
In a mechanical ____, a large effort moves a small load at a _____ speed
disadvantage
greater
in a mechanical disadvantage, a ____ effort moves a ____ load at a greater speed
large
small
in a mechanical advantage, a ____ effort moves a ____ load over a small distance
small
large
In a first-class lever, the following is true:
a) effort - load - fulcrum
b) fulcrum - effort - load
c) effort - fulcrum - load
EFL
In a second-class lever, the following is true:
a) effort - load - fulcrum
b) effort - fulcrum - load
c) fulcrum - effort - load
ELF
In a third-class lever, the following is true:
a) fulcrum - effort - load
b) effort - load - fulcrum
c) effort - fulcrum - load
FEL
Which type of lever would you see in a seesaw?
first
Which type of lever exists in a wheelbarrel?
second
First-class levers produce:
a) mechanical advantage
b) mechanical disadvantage
c) neither
d) both a and b
d
Second-class levers produce:
a) mechanical advantage
b) mechanical disadvantage
c) neither
d) both a and b
a
Third-class levers produce:
a) mechanical advantage
b) mechanical disadvantage
c) neither
d) both a and b
b
What determines whether a first class lever will produce a mechanical disadvantage or advantage?
It depends on whether the effort or the load is closer to the fulcrum.
If the effort is closer to the fulcrum (load is further from the fulcrum), the lever is at a mechanical disadvantage.
If the load is closer to the fulcrum (effort is farther from the fulcrum), the lever is at a mechanical advantage.
Which type of lever system is most common in the body?
third
Which type of lever system is the rarest in the body?
first
Which type of level system sacrifices speed and range of movement for force?
second
Which lever system produces the most force?
second
Which lever system favors speed and range of motion over force?
third
Which type of lever would be found in a pair of forceps?
third
What type of lever system is found in the flexion of the forearm?
Is this lever at a mechanical advantage or disadvantage?
third
disadvantage
What type of lever system is formed when a person stands on their toes?
Is this lever at a mechanical advantage or disadvantage?
second
advantage
The head resting on the vertebral column forms which type of lever? Is this lever at a mechanical advantage or disadvantage?
first
advantage
