Forces: Skeletal, Application, Concussion Flashcards
What are the 2 subdivisions of Mechanics?
Static
Dynamic
Kinematics
Describing motion of an object/system
Static
Object/system in a constant rate of motion, including motionless (NO ACCELERATION)
Dynamic
Object/system undergoing ACCELERATION
- speeding up,slowing down, changing direction
Kinetics
Study of FORCES acting on an object/system- cause of motion
Rigid Body Mechanics
- object/system to be perfectly rigid (can’t change shape without damaging or breaking)
- movement of the human body
Deformable Body Mechanics
Change in shape accounted for in mechanical analysis
- bouncing/hitting a ball
Biomechanics
Application of mechanical principles in hue he study of living organisms
Internal Forces
- forces that act within a system (mm.)
- can change:
shape of the body (NOT path of body)
relative position of COM “within” the object
Tensile Forces
Internal force
Pulling forces acting on the ends of an internal structure
Ex. = mm pulling on tendons
Compressive Forces
Internal force
Pushing forces acting on bands of internal structure
Ex. Bones pushing on cartilage (spinal bending)
External Forces
Forces acting on an object/system as a result of interacting with the environment
- move the body– ground rxn forces
What are 2 categories of External Forces?
Non-contact
Contact
What is the non-contact force?
Gravity
Contact Forces
Occur btw objects in contact with each other
- includes contact with air and water
- not always proportional to weight
What are the 2 components of Contact Forces?
Normal contact
Friction
Normal Contact Forces
- occur perpendicular to the line of contact
- NOT ground rxn force or always proportional to weight of object
Friction
Contact force
- parallel force btw 2 surfaces in contact
- dry, fluid, dynamic, static
Ground Reaction Force
- forces equal and opposite to muscular force- NOT normal force
- NOT always perpendicular = can be at an angle
- can be = to normal force (push-up)
Dry Friction
When no fluid is btw objects in contact
Static Friction
No movement
- maximal static
- rolling friction
Maximal Static Friction
Point of greatest amount of force applied before movement forces