3.2.2.1 Biomechanical principles

Question 1

newton’s laws

Answer 1

relationship between body and force and body’s motion in response

Question 2

newtons 1st law

Answer 2

continue at rest/uniform motion/constant velocity straight line, compelled to change by external force

force is required to change state of motion
e.g. ice skating

LAW OF INERTIA

Question 3

inertia

Answer 3

resistance object has to change in state of motion

bigger mass = greater inertia
(bigger mass = more force to overcome inertia)
inertia dependent entirely upon mass of body

Question 4

newtons 2nd law

Answer 4

magnitude & direction of force determines magnitude & direction of acceleration

acceleration & rate of change of momentum is proportional to applied force and takes place in direction of force

F = ma

LAW OF ACCELERATION

Question 5

newton’s 3rd law

Answer 5

every action = equal and opposite reaction

e.g. reaction force from ground greater than jumpers weight lifting player off floor

LAW OF REACTION/ACTION

Question 6

Ground reaction force

Answer 6

equal and opposite force exerted on a performer who applies a muscular force on the ground

Question 7

centre of mass (COM)

Answer 7

point in object = mass is distributed evenly in all directions

point of balance

flight path COM = pre determined

men = higher COM (broad shoulders) 
women = lower COM (larger hips)

Question 8

line of gravity

Answer 8

line extending vertically down from COM

Question 9

Headstand example

Answer 9

3 points of contact 
COM directly above base of support 
base support below COM = stable 
bigger base = better stability 
line of gravity (want to be above base of support) 
taller object = less stable

Question 10

stability

Answer 10

greater mass = greater stability

lesser mass = lesser stability

Question 11

4 ways COM impacts stability:

Answer 11

1. points of contact
2. base support = bigger = stable
3. line of gravity
4. taller object = less stable

Question 12

instability

Answer 12

sometimes want instability in sport

acceleration and deceleration in sport are forms of controlled instability

Question 13

4 factors affecting stability

Answer 13

1. height of COM (lower = stable )
2. position of line of gravity (central base support)
3. area of support base (contact points = larger = stable)
4. mass of performance (increase mass = stable = increased inertia)

Question 14

newtons 3 laws to sprint start:

Answer 14

1st= hold sprinter in stationary point in blocks with no external force as is still 3rd=sprinter exerting an equal but opposite reaction with ground reaction force from blocks and weight pushing down on the blocks 
2nd= movement occurs meaning acceleration leading to a change in momentum and therefore movement

Question 15

biomechanics of jumping e.g. Volleyball

Answer 15

1st: state of rest (standing) acted upon by external force (muscles contract)
2nd: greater magnitude of force applied to ground by player, greater acceleration (height jumped)
3rd: action of volleyball player pushing against ground causes equal and opposite reaction from ground, ground exerts equal force upwards