Biomechanics

Question 1

Momentum

Answer 1

Is a measure of the amount of motion possessed by a moving body and can be expressed mathematically as P = M x V

Question 2

Conservation of Momentum

Answer 2

Principle states the total momentum of two objects before and after impact are equal

Question 3

Impulse

Answer 3

The application of force over a period of time to change the momentum of an object

Question 4

Coefficient of Restitution

Answer 4

Measures the elasticity of a collision between an object and a given surface. It measures how much energy remains in the object after a collision takes place

Question 5

Newtons Second Law

Answer 5

The rate of change of acceleration to a body is proportional to the force applied to it and inversely proportional to the mass of the object (law of acceleration)
Force = Mass x Acceleration

Question 6

Newtons Third Law

Answer 6

For every action there is an equal and opposite reaction

Question 7

Force

Answer 7

the action of one object to another, it is the product of mass times acceleration, represented mathematically as; F = M x A

Question 8

Torque

Answer 8

The tuning effect created as a result of an eccentric force being applied around a pivot or axis
Torque = Force x Distance

Question 9

Moment Arm

Answer 9

The distance between where the force is applied and the axis of rotation

Question 10

Lever

Answer 10

a rigid object that is used with an axis to either multiply the mechanical force (effort) or resistance force (load) applied to it.

Question 11

Angular Momentum

Answer 11

Angular momentum = angular velocity x moment of inertia

Question 12

Angular Velocity

Answer 12

Refers to the velocity or speed of a rotating object

Question 13

Moment of Inertia

Answer 13

Refers to the resistance of a rotating object to change its state of motion
Moment of Inertia = mass of the object x radius of rotation

Question 14

Conservation of Angular Momentum

Answer 14

Means that a spinning body will continue spinning indefinitely unless an external force acts on it

Question 15

Perpendicular Distance

Answer 15

the perpendicular distance between two objects is the distance from one to the other, measured along a line that is perpendicular to one or both

Question 16

Fluid Resistance

Answer 16

the forces a fluid places on a moving object in the opposite direction to the movement, also known as drag

Question 17

Form Drag

Answer 17

resistance created by pressure differential between front and back of an object moving through fluid

Question 18

Wave Drag

Answer 18

resistance formed by creation of waves at the point where air and water interact

Question 19

Surface Drag

Answer 19

friction produced between fluid and surface of a moving object

Question 20

Boundary Layer

Answer 20

thin layer of air surrounding or ‘attached’ to the ball

Question 21

Laminar Flow

Answer 21

a type of fluid flow in which moves smoothly in individual layers or streams

Question 22

Turbulent Flow

Answer 22

flow in which the velocity at any point varies erratically

Question 23

Buoyancy

Answer 23

refers to the upward force that keeps things afloat

Question 24

Lift

Answer 24

refers to the component of force that acts perpendicular to the direction of flow, lift is created by different pressures (high/low) on opposite sides of an object due to fluid flow past the object

Question 25

Bernoulli’s Principle

Answer 25

states that as the velocity of fluid increases, the pressure of the fluid exerts on an object decreases. Velocity is inversely proportional to pressure

Question 26

Fluid

Answer 26

the natural science of fluids (liquids and gases) in motion

Question 27

Drag

Answer 27

the component of dynamic fluid force that acts in opposition to the relative motion of the object with respect to the fluid

Question 28

Pressure Differential

Answer 28

differential pressure is a pressure that is measured relative to the pressure in the atmosphere around it

Question 29

Magnus Effect

Answer 29

describes the effect of rotation on an objects path as it movies through a fluid (it applies Bernoulli’s principle to explain the effect spin has on the trajectory or the flight path of an object)

Question 30

Spin

Answer 30

when a ball is struck with an eccentric force (off centre), there is both linear and angular rotation (the rotating ball interacts with oncoming air)

Question 31

Trajectory

Answer 31

the flight path of a projectile is called its trajectory

Question 32

Eccentric Force

Answer 32

a force whose line of action does not pass through the centre of gravity of a body on which it acts

Question 33

Magnus Force

Answer 33

describes the effect of rotation on an objects path as it moves through a fluid

Question 34

Force-motion

Answer 34

When a body is acted upon by a constant force, its resulting acceleration is proportional to the force and inversely proportional to the mass (F = ma). Newton’s Second Law.

Question 35

Force-time

Answer 35

When a force is applied to a ball its momentum changes, this is called impulse and is expressed as force x time (ft).

Question 36

Inertia/Moment of Inertia

Answer 36

Inertia/moment of inertia – resistance to change in motion. Moment of inertia = resistance to rotational motion, the sum of mass and the radial distance from the axis of rotation. I = mr.

Question 37

Range of Motion

Answer 37

The type of body movements used to produce a movement (movement around the joint).

Question 38

Balance

Answer 38

The ability to neutralise forces that disturb equilibrium in order to maintain or hold its position.

Question 39

Segmental Interaction/Coordination Continuum

Answer 39

Energy that is transferred across body segments and joints in a sequence of movements (kinetic chain).

Question 40

Optimal Projection

Answer 40

When angle, velocity and height of release combine to meet the demands of the task.

Question 41

Spin

Answer 41

The term used to describe the effect of rotation on an object’s path as it moves through a fluid.