Static, equilibrium and levers Flashcards
2 conditions for equilibrium of a rigid body?
The resultant of all the forces acting on the body =0
The resultant of all the moment applied to the body =0
What is the center of gravity?
Point application of the weight force acting on the body
How can the center of gravity be determined?
By suspending an object from 2 different point, the center of gravity is the intersection of the two lines created from the suspension points when the body is at equilibrium
Where is the center of gravity located in humans?
The second sacral vertebra
What is the axis around which a rod is free to rotate on in a lever?
Fulcrum
What does conditions of translation and rotational equilibrium require?
Resultant of forces=0
Resulting momentum=0
How many classes of levers?
3
Where is the fulcrum positioned in class 1 levers?
Between the effort and the resistance
Example of class 1 lever in the body
Atlanto-occipital joint
Where is the resistance located in class 2 levers?
Between the fulcrum and the effort
Which class of levers are advantageous levers?
Class 2
Example of class 2 lever in the body
Standing on your tiptoes
Where is the effort located in class 3 levers?
Between the fulcrum and the effort
Which class of levers are disadvantageous?
Class 3
Example of class 3 levers in the body
Elbow is the fulcrum
Mandible, upper jaw is the fulcrum
