biomechanical principles

Question 1

what is newtons first law
(inertia)

Answer 1

a body will remain in a state of rest or uniform motion unless acted on by an external or unbalanced force

Question 2

what is newtons second law
(acceleration)

Answer 2

a bodys rate of change in momentum is proportional to the size of the force applied and acts in the same direction of the force applied

Question 2

what is newtons third law
(reaction)

Answer 2

for every action force applied to a body there is an equal and opposite reaction force

Question 3

what is a force

Answer 3

a push or pull that alters the state of motion of a body. All forces are measured in Newtons

Question 4

how does forces affect bodies

Answer 4

-create motion
-accelerate
-decelerate
-change direction
-change shape

Question 5

what is a net force

Answer 5

the sum of all forces acting on a body are considered. it shows the resultant force. We consider vertical and horizontal forces separately.
vertical=weight and reaction
horizontal=friction and wind resistance

Question 6

what are the forces if the net=0

Answer 6

forces are balanced

Question 7

what re the forces if the net is not 0

Answer 7

forces are unbalanced

Question 8

factors affecting friction

Answer 8

-roughness of ground surface
-roughness of contact surface
-temperature
-size of reaction force

Question 9

factors affecting air resistance

Answer 9

-velocity
-shape
-frontal cross-sectional area
-smoothness of surface

Question 10

example of a vertical force

Answer 10

-weight
-reaction

Question 11

example of a horizontal force

Answer 11

-friction

Question 12

what is the equation for weight

Answer 12

weight = mass x 9.807

Question 13

what is the equation for velocity

Answer 13

displacement / time taken

Question 14

equation for momentum

Answer 14

mass x velocity

Question 15

equation for acceleration

Answer 15

final velocity - initial velocity / time taken

Question 16

centre of mass definition

Answer 16

the point of which a body is balanced in all directions

Question 17

what are the affecting factors of centre of mass

Answer 17

-height of centre of mass
-mass of the body
-size of the base of support
-the line of gravity
-number of points of contact

Question 18

what is mechanical advantage

Answer 18

less effort is required to move a large load

Question 19

what is mechanical disadvantage

Answer 19

a large effort is required to move a small load

Question 20

does class one levers have mechanical advantage or disadvantage

Answer 20

they can have mechanical advantage or disadvantage as it depends on the position of the fulcrum which determines the length of the load and effort arm

Question 21

does class two levers have mechanical advantage or disadvantage and why

Answer 21

always have mechanical advantage as the effort arm is always bigger than the load arm

Question 22

does class three levers have mechanical advantage or disadvantage and why

Answer 22

always have mechanical disadvantage as the effort arm is always shorter than the load arm

Question 23

equation for mechanical advantage

Answer 23

load/effort

Question 24

what is limb kinematics

Answer 24

the study of movement of limbs in space, and time taken to carry out the movements. it includes the study of gait

Question 25

how does limb kinematics work

Answer 25

reflective markers are placed on the performers body landmarks and they are filmed using multiple video cameras. the data is then transferred into digital form for analysis

Question 26

is limb kinematics reliable and why

Answer 26

not reliable as there are many factors that can affect the results each time

Question 27

what are advantages of limb kinematics

Answer 27

-information is readily available -the coach can use the information to make changes in technique -can examine the effect of movements causing injury -investigates technique effectiveness

Question 28

disadvantages of limb kinematics

Answer 28

-expensive equipment -results do not take into account individuals differences -lab conditions are unrealistic

Question 29

what does limb kinematics assess

Answer 29

bone geometry, displacement, velocity and acceleration in multiple planes

Question 30

is limb kinematics valid

Answer 30

yes as long as it is done correctly and the position of the markers are precise

Question 31

what are force plates

Answer 31

measuring instruments that measure the ground reaction force generated by a body standing or moving

Question 32

what law does force plates use

Answer 32

newtons 3rd law of motion

Question 33

what are the uses of force plates

Answer 33

prevents injury and increases performance

Question 34

what are advantages of force plates

Answer 34

-optimises performance -minimises injury -accurate -enhances training -reliable -valid

Question 35

what are the disadvantages of force plates

Answer 35

-expensive -hard to use -cant tell where the force is coming from

Question 36

what are wind tunnels

Answer 36

tubular passage used to study the effects of air travelling over, under and through solid objects

Question 37

what are advantages of wind tunnels

Answer 37

-marginal gains to reduce air resistance and increase stream line to increase speed -controls cross winds -improves the flow of air around an object, reduces drag, increases lift and streamlining

Question 38

what are disadvantages of wind tunnels

Answer 38

-expensive -complex -need specialised equipment

Question 39

what does coloured smoke do in wind tunnels

Answer 39

used to see how the air interacts with an object