biomechanics

Question 1

what are biomechanics used for

Answer 1

to improve human movement and improve technique

Question 2

force

Answer 2

is a push or a pull which produces or alters movement-

mass x acceleration

Question 3

external forces that act on the body

Answer 3

• friction: 2 surfaces come into contact
• air and water resistance: body moves through air or water- drag force
• gravity: constant force that acts through the centre of mass of an object towards earth

Question 4

mass

Answer 4

how much matter and object is made up of

Question 5

inertia

Answer 5

is an objects resistance to change its state of motion-

more mass = a greater inertia

Question 6

momentum

Answer 6

a measure of the amount of motion an object has and its resistance to changing that motion-
mass x velocity

Question 7

conservation of momentum- linear

Answer 7

relates to the transfer of momentum during a collision

Question 8

summation of momentum

Answer 8

Relates to generating maximum momentum over a longer period of time. Sequential summation of momentum from the beginning of the movement to the end results in max force production

Question 9

impulse

Answer 9

When the momentum of something is changed. This can be a body or object gaining momentum or slowing down.
force x time

Question 10

Newton’s first law of motion

Answer 10

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

Question 11

Newton’s second law of motion

Answer 11

Law of acceleration- A force applied to an object will produce a change in motion in the direction of the applied force that is directly proportional to the size of the force

Question 12

Newton’s third law of motion

Answer 12

Law of action-reaction- For every action there is an equal and opposite reaction
eg. pushing off starting blocks

Question 13

Newton’s first law of angular motion

Answer 13

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

Question 14

Newton’s second law of angular motion

Answer 14

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

Question 15

Newton’s third law of angular motion

Answer 15

For every torque there is an equal and opposite torque

Question 16

what is angular momentum

Answer 16

the amount of angular motion an object has

= moment of inertia x angular velocity

Question 17

what is moment of inertia

Answer 17

How hard or easy is it for rotation to occur. It is all about how close the mass of an object is from the axis of rotation- if the mass of the object is closer to the axis of rotation, the moment of inertia decreases and it becomes easier to spin

Question 18

what is angular velocity

Answer 18

How fast the body or object is rotating

Question 19

what is linear motion

Answer 19

The movement of a body along a straight or curved path. All body parts move in the same direction at the same speed

Question 20

what does linear distance refer to

Answer 20

measures the path travelled from start to finish regardless of direction

Question 21

what does linear displacement refer to

Answer 21

measures the change in position- how far it is from the initial position to the final position

Question 22

what does linear speed refer to

Answer 22

distance covered over a particular time

Question 23

what does linear velocity refer to

Answer 23

amount of displacement over a particular time

Question 24

what is linear acceleration

Answer 24

A change in velocity over a period of time

• it can be positive- speeding up
• it can be negative- slowing down
• or zero- moving at a constant velocity

Question 25

what does angular motion involve

Answer 25

involves rotation around a central axis or a fixed point

Question 26

define torque

Answer 26

Rotation around an axis that occurs as a result of an external force being applied. If torque increases so does angular accelaration = force x lever arm length

Question 27

what is angular distance

Answer 27

the total distnce covered during angular motion- measured in degrees

Question 28

what is angular displacement

Answer 28

the difference between the starting point and the finishing point of the angular motion- measured in degrees

Question 29

what is angular speed

Answer 29

the total degress covered over a particular time

Question 30

what is angular velocity

Answer 30

the change of position over a particular time

Question 31

what is angular acceleration

Answer 31

how quickly a body or object an change its angular position- can be positive, negative or zero

Question 32

what is projectile motion

Answer 32

when a body or object is launched into the air

Question 33

what are the factors that affect the path of a projectile

Answer 33

- angle of release- affects horizontal distance - speed of release- the greater the speed of release the greater the horizontal range - height of release- difference in the height at which it is released and lands

Question 34

define equilibrium

Answer 34

when there are no unbalanced forces or torques acting on an object

Question 35

define static equilibrium

Answer 35

the body or object must not be moving or rotating and all forces and torques acting on them must be zero

Question 36

define dynamic equilibrium

Answer 36

the body or object is moving with a constant velocity

Question 37

what is stability

Answer 37

resistance to the disruption of equilibrium

Question 38

what is balance

Answer 38

the ability to control equilibrium

Question 39

examples of stability in sport

Answer 39

- swimmers use a stnace on the blocks to minimse stability so move off quickly - wrestlers use positions to increase stability so it is more difficult to disrupt equilibrium

Question 40

what are the factors that affect stability

Answer 40

- base of support - centre of gravity - body mass - friction between the body and surfaces

Question 41

base of support- affecting stability

Answer 41

generally, the lager the base of support the greater the stability of an object eg. baseball player has a wide stance to not lose balance when swinging

Question 42

centre of gravity (including line of gravity)- affecting stability

Answer 42

Generally, the lower the centre of gravity the greater the stability. When the line of gravity is through the middle of the base of support stability is increased

Question 43

body mass- affecting stability

Answer 43

the greater the mass of an object or body the more stable it is

Question 44

friction- affecting stability

Answer 44

Increasing the friction between the body and the surface it is in contact with will increase stability eg. waxing a surfboard or golf gloves

Question 45

what are levers

Answer 45

levers are simple machines that have a mechanical advantage allowing us to either: - apply a small force to move a much greater resistance - move one point of an object a small distance causing another point of the same object to move a larger distance

Question 46

mechanical advantge less than 1

Answer 46

less effort to move a resistance

Question 47

mechanical advantage greater than 1

Answer 47

increased range of motion and increased angular speed

Question 48

difference between first, second and third class levers

Answer 48

- fist class levers- can change depending on where the axis is located - second class levers- have a mechanical advantage of greater than 1 - third class levers- have a mechanical advantage of less 1

Question 49

lever length

Answer 49

increasing lever length with sporting equipment increases the resistance arm and also the moment of inertia