Biomechanics Definitions and Equations Flashcards
Definition: 1st Law of Inertia
a body will remain at rest or in constant motion unless acted upon by an external force
Definition: 2nd Law of Acceleration
A force applied to an object will produce acceleration in the direction of the force, that is directly proportional to the size of the force and inversely proportional to its mass
Equation: 2nd Law of Acceleration
Force = Mass x Acceleration
Definition: 3rd Law of Action Reaction
For every action, there is an equal and opposite reaction
Definition: Mass
The quantity of matter found within a particular body
Definition: Inertia
the resistance of a body to change its state of motion
Definition: Force
A push or pull acting on an object as a result of its interaction with another object
Definition: Normal Force
The support force exerted by one stable object on another
Definition: Applied Force
A force that is aplied to an object by a person or another object
Definition: Friction Force
The force exerted by a surface as it moves across another
Definition: Drag Force
A frictional force exerted on a moving object through air or water (air or water resistance)
Definition: Gravitational Force
A gravitational force is the force of attraction between two objects or bodies
Definition: Friction
Friction occurs when two objects come into contact with each other and it opposes motion
Definition: Weight
The force exerted on an object by gravity and is directly proportial to its mass (not the same as body weight)
Definition: Distance
The distance travelled from start to finish
Definition: Displacement
The difference between the initial position and the final position of an object
Definition: Angular Distance
Is the total of all angular changes that result from an object or body part angle bewteen the starting and finishing position
Definition: Angular Displacement
Is the difference in degrees between the object or body part’s initial and final positions
Definition: Speed
The rate of change in distance
Equation: Speed
Speed = Distance / Time
Definition: Velocity
The rate of change of displacement
Equation: Velocity
Velocity = Displacement / Time
Definition: Angular Speed
The rate of change in angular distance
Equation: Angular Speed
Angular Speed = Angular Distance / Time
Definition: Angular Velocity
The rate of change in angular displacement
Equation: Angular Velocity
Angular Velocity = Angular Displacement / Time
Definition: Acceleration
The rate of change of velocity
Equation: Acceleration
Acceleration = Change in Velocity (final - initial) / Time
Definition: Angular Acceleration
The rate of change of angular velocity
Definition: Momentum
The motion pssessed by the moving body (amount of motion in an object)
Equation: Momentum
Momentum = Mass x Velocity
Definition: Force Summation
The sequential and coordinated movement of each body segment to produce maximum velocity
Definition: Impulse
The change in momentum of an object
Equation: Impulse
Impulse = Force x Time
Definition: 1st law of angular motion
Angular momentum of a rotating body is constant unless acted upon by an external torque (rotation)
Definition: 2nd law of angular motion
A torque applied to an object will cuase a change in angular motion in te directiom of the applied torque that is directly proportional to the size of the torque applied and inversely proportional to the moment of intertia
Equation: 2nd law of angular motion
Torque = Mass x Angular Acceleration
Definition: 3rd law angular motion
For ever torque (rotation) there is an equal and opposite torque
Definition: Torque
A measure of the turning (rotational or eccentric) force applied to a body
Definition: Angular Motion
Is movement around an axis (internal or external) caused by an eccentric force
Equation: Angular Motion
Torque = Force x Moment Arm (where you apply the force)
Definition: Angular Momentum
The quantity of rotation of a body around an axis
Equation: Angular Momentum
Angular Momentum = Moment of Inertia (mass x radium^2) x Angular Velocity
Definition: Moment of Inertia
A measure of an objects reluctance to rotate
Equation: Moment of Inertia
Moment of Inertia = Mass x Radium^2
Definition: Projectile
The motion that any object or body possesses when release into the air
Definition: Equilibrium
When all forces are balanced
Definition: Balance
The ability to maintain equilirbium while stationary (static) or while moving (dynamic)
Definition: Stability
The resistance to the change (disruption) of equilibrium
Definition: Centre of Gravity
The centre point of an object, about which all of its wieght is evenly distributed and balanced
Definition: Line of Gravity
An imaginary line which passes thorugh the centre of gravity and continues down into the centrea of an objects base of support
Definition: Base of Support
The area of an object that is in contact with the surface supporting it
Definition: Lever
A lever is a simple machine that consists of a rigid beam that roates around a fixed point (axis)
Definition: 1st Class Lever
A lever where the axis is located between the force and resistance and has a mechanical advantage = 1 and thus can be a force or speed amplifier
Definition: 2nd Class Lever
A lever where the resistance arm is less than the force arm, that is, the resistance is acting closer to the axis than the force. The mechanical advantage is greater than one and has a mechanical advantage where it acts as a force amplifier
Definition: 3rd Class Lever
A lever where the resistance arm is greater than the force arm, that is, the resistance is acting further from the axis than the force. The mechanical advantage is less than one therefore has a mechanical disadvantage and is a speed amplifier.
Equation: Mechanical Advantage
Mechanical Advantage = Force Arm / Resistance Arm
