U3 AOS 2: Biomechanics Flashcards
Motion
refers to a body’s change in position in relation to time.
Linear motion
(also commonly referred to as translation)
occurs in either a straight line or curved path
Angular motion
(also commonly referred to as rotation)
takes place when a body moves along a circular path
General motion
is the combination of linear and angular motion
Mass
the quantity of matter found within a particular body
Inertia
the resistance of a body to a change in its state of motion
Force
formula: F=ma
a push or pull on an object or body
Distance
the length of space between two points
Displacement
the difference between the initial position and the final position of an object
Speed
formula: distance / time
OR: linear speed = angular velocity x radius of rotation
time taken to cover a certain distance
Velocity
formula: displacement / time
the rate of speed at which an object moves its position
(LINEAR) Acceleration
formula: final velocity - (initial velocity) / time
refers to the rate of velocity change experienced by an object over time.
Momentum
formula: (p)= mass (m) x velocity (v)
describes the quantity of motion a particular body of mass has
Force summation (summation of momentum)
refers to the correct timing and sequencing of body parts to produce maximal force
Impulse
formula: force x time
the product of force and time, and is equal to the change in momentum of an object
Eccentric force
a force that is off-centre or not directly through an object’s centre of mass
Centre of mass
the position where the weight of the object is evenly distributed
Torque
formula: force x moment arm
a force that is applied at a distance away from the centre of mass, that causes the object to rotate
Angular distance
the angle between the initial and final position of a body/object.
Angular displacement
the change of angle between the initial and final position of a body/object
Angular speed
refers to the angular distance covered divided by the time taken.
Angular velocity
formula: (initial angle - final angle) / time
NEEDS A DIRECTION
the change in angular displacement over time, which indicates how quickly an object rotates
Angular acceleration
formula: (final velocity - initial velocity) / time
NEEDS A DIRECTION
is the rate of change of angular velocity (final velocity − initial velocity) over time.
Angular momentum
formula: moment of inertia (MOI) x angular velocity (AV)
is a measure of how much rotation a body has around an axis
Moment of inertia
formula: mass x radius ^2 (radius squared)
is a measure of an object’s resistance to change in its rate of rotation
Conservation of angular momentum
the principle of conservation of momentum says that while airborne there will be NO change of angular momentum.
Newton’s first law of motion
Inertia
states an object will stay at rest or continue to travel in the same direction at a constant velocity unless acted on by an unbalanced force
Newton’s second law of motion
F=ma
states that the rate of acceleration of a body is proportional to the force applied to it and in the direction in which the force is applied
Newton’s third law of motion
states that for every action there is an equal and opposite reaction (force)
Lever
a lever is a rigid bar that allows the application of either increased force and/or speed
Mechanical advantage
formula: force arm/resistance arm
mechanical advantage is a measure of how much a lever amplifies force.
Static equilibrium
the state in which a body has zero velocity and zero acceleration. A body in equilibrium when the sum of all movements acting on the body are zero
Dynamic equilibrium
the state in which a body is in motion with a constant velocity
Stability
the degree to which a body resists changing its equilibrium
Balance
the ability to control the state of equilibrium
Centre of gravity (COG)
is the central point of an object around which all of its weight is evenly distributed and balanced
The line of gravity
is an imaginary line that passes through the centre of gravity and continues down into the centre of an object’s base of support
The base of support
refers to the area of an object that is in contact with the surface supporting it
