Lecture 6 Flashcards
Biomechanics
Application of mechanical laws to living structures, specifically to the locomotor system of the human body
Qualitative movement analysis
Non-numerical description of a movement based on direct observation (coaching watching you at tryout)
Quantitative movement analysis
A movement is analyzed numerically based on measurement from data (stats)
Mass
The quantity of matter contained in an object
-Units = Kg
Force
Mass x Acceleration
Units (Newtons) N
- 1N = (1Kg)(1m/s^2)
Weight
The amount of gravitational force exerted on a. body
Weight = mass x acceleration of gravity
9.81m/s^2
Volume
The amount of space that a body occupies
Pressure
Force distributed over a given area
-Pressure = F/A
(units N/m^2) (N/cm^2)
Compression
Pressing or squeezing force directly axially through a body
Tension
Pulling or stretching force directly axially through a body
Shear
Force directed parallel to a surface
Mechanical stress
F/A Similar to pressure
3 Point in a lever
Force Point (F) = where force is applied Resistance point (R) = where the resistance acts Fulcrum (A) = the Axis of motion
First class Lever (Arf)
Fulcrum is between force point and resistance point
Seesaw
Second class lever (aRf)
Resistance point is between the force point and the fulcrum.
Wheel barrow
3rd class Lever (arF)
Force point is between the resistance and the fulcrum
Mechanical advantage
The efficiency with which a lever is able to magnify forces is described by its mechanical advantage
Force arm/Resistance arm
Force lever
When FA is longer than RA,
Favors force
sacrifices speed
Speed lever
RA is longer than FA
Favors speed and range of motion
Sacrifices force
Moment arm
The perpendicular distance between the force’s line of action and the axis of rotation
Torque
The product of force and the perpendicular distance (moment arm ) from the force’s line of action to the axis of rotation. IT may be thought of as rotary force.
= Force (N) x Moment arm (m)
Centre of gravity
The point of intersection of 3 cardinal planes of the body
The point of exact centre around which the body may rotate freely in all directions
The point around which the weight is equal on all opposite side
Newton’s first Law of motion
Law of inertia
Amount of inertia a body possess is directly proportional to its mass. An object at rest will remain at rest
Second law - Law of Acceleration
Force = mass x acceleration
More force more acceleration
3rd Law - Law of reaction
When a body exerts a force onto something, the second body exerts the same force
Momentum
Quantity of motion that an object possess
Mass x Velocity
Work
Force x distance
Units of work - 1.0 J
Power
Work per unit of time
(Force x distance) / t
Unit of power = watt = j/sec
