4. Biomechanical Principles Notes Flashcards
What is motion?
change in position of a body in relation to time
What is linear motion?
When a body and its parts move in a line (straight or curved)
What paths can linear motion be?
Rectilinear (straight) and curvilinear (curved)
What is angular motion?
When a body and its parts move in a full or partial circle about an axis of rotation
What are the two types of axis in angular motion?
Internal and external axis
What is general motion?
When linear and angular motion are occurring at the same time
What is mass?
Describes the quantity of matter find within a particular body
What is inertia?
The reluctance of the body to change its state of motion; closely linked to an objects mass
What is force?
Created by a push or pull a cause an object to change in motion
What is the unit of force?
Newtons
What is eccentric force?
A force that is applied away from an objects centre of gravity
What is distance?
Path travelled from start to finish
What is displacement?
The change in position
What is angular distance?
Angle between initial and final position
What is angular displacement?
Change of angle between initial and final position
What is speed?
time taken to cover a certain distance
What is velocity?
Time taken to change position
What is angular speed?
Angular distance covered divided by the time taken
What is angular velocity?
Change in angular displacement over time
What is acceleration?
A change in velocity in a given period of time
What is angular acceleration?
The rate of change of angular velocity over time
What is momentum?
The quantity of motion a particular body of mass has
What is conservation of momentum?
Whenever two bodies collide, their combined momentum is conserved
What is summation of momentum?
Refers to the correct timing and sequencing of body parts to produce maximal force
What is moment of inertia?
A body’s resistance to change in rotation
What is angular momentum?
Measure of how much rotation a body has around an axis
What is conservation of angular momentum?
The alterations of the moment of inertia or angular velocity, but the angular momentum staying the same
What is impulse?
A change in force over time
What is a momentum breaker?
Increasing time to reduce the force - follow through
What is a momentum maker?
Increasing the change in momentum of an object to its maximum
What is Newton’s first law
The law of inertia
A body will remain at rest or in uniform motion unless acted upon by an external force
What is Newton’s second law?
The law of acceleration
A force applied to an object will produce a change in motion (acceleration) in the direction of the applied force that is directly proportional to the size of the force
What is Newton’s third law?
For every action there is an equal and opposite reaction
What is projectile motion?
Any movement of an airborne body that is only affected by the forces of gravity and air resistance
What factor of projectile motion does gravity affect?
Vertical distance
What factor of projectile motion does air resistance affect?
Horizontal
What is height of release?
The height from which a projectile is released
What is speed of release?
The release speed of a projectile which has a vertical and horizontal component
What is angle of release?
angle at which an object is hit, kicked, thrown or launched into the air
When is an angle of less than 45 optimal?
When the target is lower than take off
When is an angle of 45 degrees optimal?
When target and takeoff are on the same level
When is an angle of more than 45 degrees optimal?
When target is higher than take off
What is a lever?
A system or machine consisting of a rigid bar that can be made to rotate around an axis
What are the three parts of a lever?
Axis, resistance and force
What are the main functions of an anatomical lever?
- to generate muscular effort
- to increase speed of a given moment
What are the parts of a lever in the human body?
Joint = axis
Weight of a body part or sporting equipment = resistance
Muscles = force
Where is the force in a third class lever?
In the middle of the lever
What is the purpose of a third class lever?
To amplify speed
What is mechanical advantage?
The ratio of the force arm to the resistance arm
what is the mechanical advantage of a third class lever?
Less than one
