biomechanical principles and levers

Question 1

linear motion definition

Answer 1

motion in a straight or curved line where all body parts move in same distance, speed and direction

Question 2

explanation of newtons first law

Answer 2

law of inertia-force is required to change state of motion

if object at rest will remain still

if moving in one direction will continue at same velocity until force is exerted upon it

bigger the mass, harder it is to overcome inertia as more force needed to change state of motion

e.g. sumo wrestler

makes bigger impact when inertia is overcome as the large mass makes a bigger fall

Question 3

inertia definition

Answer 3

resistance an object has to a change in its state of motion

Question 4

newtons second law of motion

Answer 4

law of acceleration

magnitude (size) and direction of force determines magnitude and direction of acceleration

rate of acceleration is directly proportional to force causing change

mass remains constant, then acceleration is equal to force causing it

runner must have large force to allow themselve to accelerate

Question 5

equation to work out the size of a force

Answer 5

force=mass x acceleration

Question 6

newtons third law

Answer 6

law of reaction

for every action (force)there is an equal and opposite reaction (force)

describes what happens when two bodies exert forces on one another

action acts on one body, reaction acts on the other body

Question 7

sport example of law of reaction

Answer 7

runner pushes down on starting blocks (action)

blocks push forward on the athlete (reaction)

many questions of law of reaction mention GRF (ground reaction force)

Question 8

Ground reaction force (GRF) definition

Answer 8

force exerted on the ground by the body in contact with it

Question 9

sport example of 1st law

Answer 9

penalty

ball remains still (state of rest) until force exerted upon it (kicked by player)

Question 10

sport example of 2nd law

Answer 10

when player kicks ball, acceleration of the ball is equal to size of the force

Question 11

sport example of 3rd law

Answer 11

header

when football jumps up (action)
force exerted on ground to gain height
same time, ground exerts an upward force (equal and opposite) upon the player

Question 12

scalar quantity definition

Answer 12

when measurements are described in terms of just their magnitude and size

DIRECTION NOT TAKEN INTO ACCOUNT

Question 13

speed definition

Answer 13

rate of change of position

Question 14

speed equation

Answer 14

distance covered (m) divided by time taken (s)

Question 15

distance

Answer 15

length of the path a body follows when moving from one position to another

Question 16

distance calculation

Answer 16

distance=speed x time

Question 17

centre of mass

Answer 17

point of balance

body constantly moving, so centre of mass constantly changing

body irregular shape so hard to identify centre of mass

Question 18

factors affecting stability

Answer 18

height of centre of mass-lowering centre of mass increases stability

position of line of gravity-should be central over base of support to increase stability

area of support base-more contact points, larger base of support, increase in stability e.g headstand more balanced then handstand as has more contact points so more stability

mass of the performer-greater mass, more stability as increased inertia

Question 19

what are the 3 components of a lever

Answer 19

EFL THE ELF FEL
bones-levers
effort-muscles
fulcrum-joint
load-weight of body part being moved

Question 20

first class lever

Answer 20

EFL

where the fulcrum (joint) is located between the effort(muscles) and the resistance(body part)

Question 21

movement in first class lever

Answer 21

movement of head and neck during flexion and extension
extension of elbow

Question 22

second class lever

Answer 22

ELF

this is where the load is located between both the effort and the fulcrum

Question 23

movement in second class lever

Answer 23

plantarflexion in ankle only

Question 24

third class lever

Answer 24

FEL

this is where the effort is located between the fulcrum and load

Question 25

movement in third class lever

Answer 25

hip knee and elbow flexion

Question 26

mechanical advantage

Answer 26

where force arm is longer then resistance arm

means lever system can move large load but over short distance and requires little force

Question 27

mechanical disadvantage

Answer 27

reisistance arm is longer then force arm

cannot lift as heavy but faster

Question 28

what is the force arm

Answer 28

shortest distance between fulcrum and effort

Question 29

what is the resistance arm

Answer 29

shorted distance between fulcrum and resistance