Biomechanics

Question 1

Force

Answer 1

A push or pull

Question 2

Force equation

Answer 2

Force = Mass x Acceleration

Question 3

Friction

Answer 3

Occurs when two forces come together

Question 4

Force affect objects in 2 ways

Answer 4

• Change the shape of the object (stretch, squash, twist)
• Move the object (start moving, speeds up, change direction)

Question 5

Air and water resistance

Answer 5

When an object travels through air or water (or
gas/fluid) it will experience drag force

Question 6

Drag force

Answer 6

Opposes direction of object – slows it down

Question 7

Gravitational force

Answer 7

Force of attraction between two bodies or objects
-Acceleration due to gravity is 9.8 m/s²

Question 8

Mass

Answer 8

The amount of matter an object is made up of

Question 9

Weight

Answer 9

the force that is exerted on the body by gravity

Question 10

Weight equation

Answer 10

Weight = mass x gravity

Question 11

Inertia

Answer 11

The tendency for a body to resist a change in its state of
motion (rest or moving)
Greater inertia = harder to stop
Amount of inertia is related to its mass

Question 12

Momentum

Answer 12

The amount of motion an object has and its resistance to changing that motion

Question 13

Momentum equation

Answer 13

momentum = mass x velocity

Question 14

Conservation of momentum

Answer 14

Total momentum of the system before the collision is equal to the total momentum after the collision

Question 15

Summation of momentum

Answer 15

Any movement skill that involves multiple joints requires summation of momentum from the beginning to the end
- By coordinating all body segments that are involved inthe movement – you are able to generate maximum
velocity

• momentum generated in sequential order

-Body parts closest to the centre of gravity to those further away

• Ideally we want maximum velocity at impact or release

Question 16

Impulse

Answer 16

Equal to the change in momentum of an object

Question 17

Impulse equation

Answer 17

Impulse = force x time

Question 18

Newtons first law of motion (Law of inertia)

Answer 18

A body will remain at rest or in uniform motion in a
straight line unless acted upon by an external force

Question 19

Newtons second law of motion (Law of acceleration)

Answer 19

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

Question 20

Newtons third law of motion (Law of action-reaction)

Answer 20

For every action there is an equal and opposite reaction

Question 21

Moment of inertia

Answer 21

For every action there is an equal and opposite reaction

Question 22

Moment of inertia equation

Answer 22

Moment of inertia = mass x radius squared

Question 23

First law of angular motion

Answer 23

The angular momentum of a body remains constant unless acted upon by an external torque

Question 24

Second law of angular motion

Answer 24

A torque applied to an object will produce a change in angular motion that is directly proportional to the size of the torque and inversely proportional to the moment of inertia in the object

Question 25

Third law of angular motion

Answer 25

For every torque there is an equal and opposite reaction

Question 26

Projectile motion

Answer 26

Object or body that is launched into air and affected by only the forces of gravity and air resistance

Question 27

Linear motion

Answer 27

Movement of a body along a straight or curved path where all body parts move in the same direction at the same speed

Question 28

Distance

Answer 28

Path travelled from start to finish regardless of direction

Question 29

Displacement

Answer 29

Change of position

Question 30

Speed

Answer 30

ratio of distance covered to time taken speed = distance/time

Question 31

Velocity

Answer 31

ratio of displacement, or change of position, to time taken velocity = displacement/time

Question 32

Linear acceleration

Answer 32

Change in velocity in a given time period Acceleration = change in velocity / change in time

Question 33

Angular motion

Answer 33

Component of general motion and involves rotation around a central axis or fixed point

Question 34

Torque

Answer 34

tendency of an object to rotate

Question 35

Torque equation

Answer 35

torque = force x lever arm

Question 36

Angular distance

Answer 36

sum of all the angular changes the body undergoes

Question 37

Angular displacement

Answer 37

difference between the initial and final angular position of an objects

Question 38

angular speed equation

Answer 38

angular distance covered / time taken to complete the motion

Question 39

angular velocity equation

Answer 39

angular distance covered / time taken to complete the motion

Question 40

Factors affecting the path of a projectile

Answer 40

Angle of release Speed of release Height of release

Question 41

Equilibrium

Answer 41

When there are no unbalanced forces or torques acting on it

Question 42

Static equilibrium

Answer 42

When body or object not moving or rotating

Question 43

Dynamic equilibrium

Answer 43

When body or object moving with a constant velocity (no change in speed or direction)

Question 44

Stability

Answer 44

The resistance to the disruption of equilibrium

Question 45

Balance

Answer 45

The ability to control equilibrium

Question 46

Factors affecting stability

Answer 46

Base of support Centre of gravity Body mass Friction between the body and the surface(s) contacted`

Question 47

Base of support

Answer 47

Larger the base of support = greater the stability

Question 48

Centre of gravity

Answer 48

The point around which its weight is balanced – regardless of the position of the body Generally found close to navel The higher the centre of gravity the less stable the body will be The lower the centre of gravity = more balanced and stable

Question 49

Body mass

Answer 49

The greater the mass of an object or body the greater the force required to move it Greater mass = most stable

Question 50

Enhancing equilibrium

Answer 50

Increase size of base support Ensuring line of gravity falls within the base of support Lowering the centre of gravity Increasing mass Increasing friction between body and surface Extending base of support in direction of oncoming force Shifting line of gravity towards oncoming force

Question 51

Levers

Answer 51

Machine consisting of a rigid bar that can be made to rotate around an axis in order to extend a force on another object

Question 52

All levers have 3 parts:

Answer 52

An axis (or fulcrum or pivot point) A resistance (or weight or load to be moved) A force (or effort)

Question 53

First class lever

Answer 53

the resistance and the force are on either side of the axis

Question 54

Second class lever

Answer 54

the resistance is between the force and the axis

Question 55

Third class lever

Answer 55

the force is between the resistance and the axis

Question 56

Mechanical advantage

Answer 56

= force arm / resistance arm

Question 57

Mechancial advantage > 1

Answer 57

Less force required to move a resistance

Question 58

Mechancial advantage < 1

Answer 58

Increase range of motion Increase speed/