Biomechanics key terms

Question 1

Angular momentum

Answer 1

the quantity of rotation a body possesses, and is a product of inertia and angular velocity

Question 2

Moment of inertia

Answer 2

the body’s reluctance to rotate/ alter its rate of rotation

Question 3

Angular velocity

Answer 3

The rate of rotation of a body around its axes of rotation

Question 4

Angular acceleration

Answer 4

The rate of change of angular velocity

Question 5

Angular displacement

Answer 5

the smallest change in angle between starting and finishing point

Question 6

Principle of conservation

Answer 6

states that angular momentum remains constant, if moment of inertia decreases, angular velocity increases visa versa

Question 7

Angular momentum equation

Answer 7

angular momentum = moment of inertia x angular velocity

Question 8

Angular velocity equation

Answer 8

Angular velocity = angular displacement /time taken

Question 9

Angular acceleration equation

Answer 9

angular acceleration = change in angular velocity / time taken

Question 10

How do you calculate angular displacement?

Answer 10

1 radian = 57.3 degrees

Question 11

Fluid mechanics

Answer 11

Study of an object as it moves through liquid/gas

Question 12

Surface drag

Answer 12

friction between the surface of an object and the environment (e.g shaving legs)

Question 13

Form drag

Answer 13

impact of the fluid environment on the object (e.g streamline)

Question 14

Projectile motion

Answer 14

refers to the movement of either an object or human body through air

Question 15

Parabola

Answer 15

uniform curve that is symmetrical at its highest point

Question 16

Impulse

Answer 16

change in momentum of object when the object is acted upon by a force for a period of time

Question 17

Impulse equation

Answer 17

impulse = force x time

Question 18

What is the Bernoulli principle?

Answer 18

covers lift force and downward force

Question 19

Law of Inertia (1)

Answer 19

the resistance an object has to change in its state of motion
- object will remain stationary until force is applied to it

Question 20

Law of acceleration (2)

Answer 20

size and direction of the force applied is directly proportional to the force causing change
force = mass x acceleration

Question 21

Law of action/ reaction (3)

Answer 21

to every action there is an opposite and equal force
e.g ground reaction force

Question 22

Speed

Answer 22

rate of change of position

Question 23

Distance

Answer 23

length of path a body follows when moving from 1 position to another
distance = speed x time

Question 24

Centre of mass

Answer 24

point of concentration of the mass/ point of balance of the body

Question 25

External forces

Answer 25

forces from outside the body

Question 26

Internal forces

Answer 26

Forces from within the body (e.g muscle contractions)

Question 27

Static friction

Answer 27

force exerted on 1 surface by another when there is no motion between the two surfaces

Question 28

Sliding friction

Answer 28

occurs when dry friction acts between 2 surfaces that are moving relative to each other

Question 29

Angular motion

Answer 29

occurs as a result of torque.

Question 30

Torque

Answer 30

rotational consequence as a result of force torque (Nm) = size of force x moment arm

Question 31

Moment arm

Answer 31

perpendicular distance from fulcrum to where force is applied (larger the distance the larger the torque)

Question 32

Linear motion

Answer 32

motion in a straight line or curved line, with all body parts moving in the same direction at the same speed and same distance

Question 33

First class lever

Answer 33

Fulcrum is positioned between the effort and resistance (load)

Question 34

Second class lever

Answer 34

Load between fulcrum and effort

Question 35

Third class lever

Answer 35

Effort between fulcrum and load

Question 36

First class lever example

Answer 36

Extension at elbow

Question 37

Second class lever example

Answer 37

Plantar flexion

Question 38

Third class lever example

Answer 38

Flexion at elbow

Question 39

Mass

Answer 39

quantity of matter in the body (kg)

Question 40

Weight

Answer 40

the gravitational force exerted on an object (N)

Question 41

Velocity

Answer 41

rate of change of displacement (m/s)

Question 42

Acceleration

Answer 42

the rate of change of velocity (m/s squared)

Question 43

Momentum

Answer 43

the product of the mass and velocity of an object (Kgm/s)

Question 44

Friction can be affected by:

Answer 44

surface characteristics temperature of surfaces mass of objects that are sliding

Question 45

Air resistance

Answer 45

opposes the motion of an objects that move through air

Question 46

Air resistance is affected by

Answer 46

velocity shape and characteristics of moving body cross-sectional area of the moving body

Question 47

Impulses can be increased by:

Answer 47

less time, more force An increase in impulse will result in an increase in the rate of momentum, causing changes to velocity. Therefore impulse is equivalent to a change in momentum of a body as a result of a force acting upon it

Question 48

Horizontal displacement

Answer 48

the shortest distance from starting point to the finishing point in a line parallel to the ground

Question 49

If landing height is higher than release height what is the optimum release point?

Answer 49

optimum release point is above 45 degree

Question 50

If release height and landing height are the same what is optimum release point?

Answer 50

optimum release point is equal to 45 degrees

Question 51

if release height is higher than landing height what is optimum release point?

Answer 51

optimum release point is below 45 degrees

Question 52

Factors affecting horizontal displacement:

Answer 52

angle of release speed of release (greater the release velocity - greater the horizontal displacement) height of release (greater the release height = increase in horizontal displacement)

Question 53

Factors reducing drag:

Answer 53

* Velocity of moving body * Cross-sectional area of moving body * Shape and surface * Characteristics of the moving body

Question 54

Factors affecting stability:

Answer 54

Height of centre of mass Area of base of support Position of line of gravity Body mass