biomechanics

Question 1

what is a force

Answer 1

a push or a pull that alters the state of a body

Question 2

what is inertia

Answer 2

the resistance of a body to change its state of motion , either at rest or whilst moving

Question 3

what is velocity

Answer 3

the rate of change in displacement

Question 4

what are newtons three laws

Answer 4

law of inertia , law of acceleration & law of reaction

Question 5

what is newtons first law

Answer 5

law of inertia

Question 6

what is newtons second law

Answer 6

law of acceleration

Question 7

what is newtons third law

Answer 7

law of reaction

Question 8

what is newtons first law of inertia

Answer 8

a body will continue in a state of rest or uniform velocity unless acted upon by external force
- greater the mass , greater the inertia therefore the greater fore needed to change the body’s state of motion

Question 9

what is newtons second law of acceleration

Answer 9

a body’s rate of change in momentum is proportional to the size of the force applied and it acts in the same direction as the force applied
- the more force , the more acceleration and the bigger the change in momentum

Question 10

what is newtons third law of reaction

Answer 10

for every action force applied to a body, there is an equal and opposite reaction force generated by the object back towards the body

Question 11

how does mass effect inertia

Answer 11

the greater the mass of an object, the larger its inertia therefore a greater force is needed to change its state of motion

Question 12

how do you calculate velocity

Answer 12

displacement / time taken

Question 13

how to calculate momentum

Answer 13

mass x velocity

Question 14

how to calculate acceleration

Answer 14

(final velocity - initial velocity) / time taken

Question 15

how to calculate force

Answer 15

mass x acceleration

Question 16

what are the two types of forces

Answer 16

internal and external

Question 17

what are internal forces

Answer 17

forces generated by the contraction of skeletal muscle

Question 18

what are external forces

Answer 18

forces that come from outside of the body and acts upon it

Question 19

what are the 5 effects of force

Answer 19

• can create motion
• can accelerate a body
• can decelerate a body
• can change the direction of a body
• can change the shape of a body

Question 20

what is net force

Answer 20

the sum of all forces acting on a body

Question 21

if net force is zero

Answer 21

the forces are balanced

Question 22

if the net force is present…

Answer 22

… the force are unbalanced and the body is accelerating/decelerating/ changing shape or direction

Question 23

what does a positive net force mean

Answer 23

body is accelerating

Question 24

what does a negative net force mean

Answer 24

body is decelerating

Question 25

what are the two vertical forces

Answer 25

weight and reaction

Question 26

what is weight

Answer 26

gravitational pull that the earth exerts on a body

Question 27

how does weight act

Answer 27

downwards force from the bodys centre of mass

Question 28

how does reaction act

Answer 28

upwards force from the bodys point of contact with surface

Question 29

what are the two horizontal forces

Answer 29

friction and air resistance

Question 30

in what direction does friction act

Answer 30

same direction as the direction of motion from the point of contact

Question 31

what affects friction

Answer 31

- roughness of the surface - roughness of contact surface - temperature - size of normal reaction

Question 32

in what direction does air resistance work

Answer 32

against the direction of motion from the bodys centre of mass

Question 33

what affects air resistance

Answer 33

- velocity - shape of body - frontal cross section of body - smoothness of surface

Question 34

what does it mean if net force is zero

Answer 34

body is at rest/ travelling at uniform velocity

Question 35

how can an athlete increase/maximise their power

Answer 35

through weight/plyometric training - uses the speed and force of different movements to increase muscle power more muscle power - more action force therefore more reaction force/acceleration

Question 36

what is centre of mass

Answer 36

the point where all forces are balanced- dependant on the distribution of body mass

Question 37

how can the centre of mass be manipulated

Answer 37

by altering the body shape ie stretching/bending

Question 38

what is stability

Answer 38

the ability of a body to remain at rest and resist motion

Question 39

what is stability affected by

Answer 39

• mass of body • line of gravity • points of contact • height of COM • base of support

Question 40

how does mass effect stability

Answer 40

more mass - more stable

Question 41

how does centre of mass affect stability

Answer 41

the lower the COM- the more stable

Question 42

how does line of gravity effect stability

Answer 42

the closer the line to centre of mass - the more stable ie lean forward

Question 43

how does the base of support effect stability

Answer 43

wider the base - more stable

Question 44

how does points of contact effect stability

Answer 44

more points of contact - more stable

Question 45

what is the line of gravity

Answer 45

an imaginary line that extends from the centre of mass to the floor

Question 46

how does like of gravity and base of support link

Answer 46

the more central the line is to the base of support - more stable

Question 47

what is 123FLE

Answer 47

1 class, 2 class, 3 class fulcrum, load, effort

Question 48

what are levers

Answer 48

systems that are the coordinated of our bones and muscles - to primarily make movement

Question 49

what are the functions of levers

Answer 49

• to generate muscular effort to overcome a given load • to increase the speed of a given movement

Question 50

what are the components of the lever in the body

Answer 50

lever (bone) fulcrum (joints) effort (muscular effort used) load (weight/resistance)

Question 51

what is a first class lever

Answer 51

when the fulcrum is in the middle of the effort and load

Question 52

what is a second class lever

Answer 52

when the load is in the middle of the fulcrum and effort

Question 53

what is a third class lever

Answer 53

when effort is in the middle of the fulcrum and the load

Question 54

when is there a mechanical advantage

Answer 54

when the effort arm is longer than the load arm (second class levers)

Question 55

when is there an mechanical disadvantage

Answer 55

when resistance is more than effort 3rd class levers)