Biomechanics

Question 1

Mass

Answer 1

The amount of matter an object is made up of

Question 2

inertia

Answer 2

The tendency for an object to resist its change in emotion.

Question 3

relationship between mass and inertia

Answer 3

the greater the mass of an object the greater its inertia.

Question 4

force

force (definition, equation, how it affects objects)

Answer 4

force= mass x acceleration
- force can be described as a push or pull on an object
1. changes the shape of an object
2. change an objects motion/speed (acceleration, negative acceleration)
3. change an objects direction

Question 5

internal force

Answer 5

internal force can be described as muscles pulling on bones at a joint.

Question 6

external force

Answer 6

1. AIR AND WATER RESISTANCE (DRAG FORCE) is a frictional force that occurs when one of the surfaces is air or water.
   drag force opposes the direction of motion.
2. FRICTION occurs when two surfaces contact each other.
3. GRAVITATIONAL FORCES is when there is a constant downward force acting on objects at 9.8m/s

Question 7

motion definition and the 3 types

Answer 7

refers to the change in position of an object/body in relation to time.
- linear motion
- angular motion
- general motion

Question 8

acceleration

definition and equation

Answer 8

an object positively changing its motion. change in velocity over a period of time
- acceleration = change in velocity/change in time

Question 9

deceleration

Answer 9

something decreasing motion

Question 10

velocity

definition and equation

Answer 10

speed with direction. Time taken to change position
- velocity = displacement/time

Question 11

linear motion

Answer 11

something moving in a straight line or curved path. all parts travel the same distance at the same time in the same direction.

Question 12

angular motion

Answer 12

1. when a body part rotates around its central axis
2. an object/body twist or rotates around an axis

Question 13

Newtons first law of inertia

Answer 13

an object will stay at rest or continue to travel in the same direction at a constant velocity unless acted on by an unbalanced/external force.
1. the greater the mass of an object the greater the inertia hence the more force required to change the motion of the object with a greater inertia.
2. If an object is at rest (no motion) it will remain at rest.
3. If an object is in motion, it has a tendency to remain in motion

Question 14

Newton’s second law of force and acceleration

Answer 14

The rate of acceleration of a body/object is proportional to the force applied to it and the direction to which the force is applied (force= mass x acceleration)

Question 15

Newton’s third law of Action/Reaction

Answer 15

when two objects come in contact with one another, they exert forces that are equal in size but opposite in direction to each other. For every action, there is an equal and opposite reaction.

Question 16

moment of inertia

Answer 16

resistance of a body to change its angular rotation

Question 17

linear momentum

definition and equation

Answer 17

objects with greater momemtum are harder to stop
mass x velocity
- if an object is stationary it has zero momentum
- if ojects have the same mass, the object with greater velocity will have the greatest momentum
- if two objects have the same velocity, the object with the greatest mass will have the greatest momentum.

Question 18

angular momentum

equation

Answer 18

angular velocity x moment of inertia

Question 19

angular velocity

Answer 19

rate of rotation around an axis, measured in RPM

Question 20

Conservation of momentum

Answer 20

• when two objects come into contact the total mmomentum that existed before the collision equals the total momentum after.
• momentum is trandferred from one object to another depending which objects has teh greater mass/velocity. However momentum post contact is conserved.

Question 21

impulse

definition, equation

Answer 21

impluse= force x time
- appling force for longer (impulse) results in a change of momentum.
- impulse can be applied to an object to either increase or decrease the momentum of the object
injury prevention
absorbing force over time (force x time) will decrease the momentum of an object or body. the force is absorbed overtime
eg a crash mat will absorb the impact force over a longer period of time, they will still come to resr but with less risk of injury because of the smaller impact force.

Question 22

Summation of momentum

Answer 22

summation of momentum
1. BODY PARTS use as many body parts as possible
2. SEQUENCE- move larger (slower) stronger body parts first eg quads. followed by the smaller (faster) body parts eg hand
3. TIMING move the next body part, only when the previous part has reached maximum velocity
4. STABILIZATION - body parts must be stabilised so that momentum is not lost.
5. appropriate follow through to avoid decleration and loss of momentum

Question 23

Application of summation of momentum

Answer 23

• activate larger body to smaller body parts in a sequence
• this will increase impulse (fxt) as force is being applied for longer
• greater impulse (fxt) will result in an increase in momentum (mxv) and velocity of body parts
• increases agular velocity and momentum of the arm and transfers to the ball
• increases linear velocity of the ball
• ball will fly further and faster

Question 24

Projectile motion

definition

Answer 24

when an object is launched into the air, it becomes a projectile that is affected by air resistance and gravity

Question 25

Path and distance are impacted by these 3 factors

Answer 25

1. speed of release 2. angle of release 3. height of release

Question 26

Angle of release | release height and landing angles

Answer 26

45 deg if landing is the same and release height. less than 45 deg if release height is above landing height. greater than 45 deg if release heigh tis lower than landing height

Question 27

factors influencing projectile motion

Answer 27

- velocity - mass - shape - surface area - nature of surface area

Question 28

how do you improve balance and stability

Answer 28

1. lower your centre of gravity by bending your knees 2. widen your base of support by taking feeting further apart 3. ensure line of centre of gravity is withing base of support

Question 29

describe first clss levers (type) | one example

Answer 29

levers have the axis as the central componemnt that separates the force and resistance RAF eg crow bar

Question 30

describe second class levers (type) | one example

Answer 30

levers have the resistance as the central component that separates the axis and force ARF eg plantar flexion in a calf raise

Question 31

describe third class levers (type) | an example

Answer 31

levers have the force as the central component that separates the axis and the resistance AFR eg throwing a ball

Question 32

what do 1st and 2nd class levers do

Answer 32

- assist in decreasingteh amount of force required to move a mass - FORCE MULTIPLYER - more force can be applied for less effort - mechanical advantage of more that 1

Question 33

force arm | definiton

Answer 33

distance between the axis and the force

Question 34

resistance arm | definition

Answer 34

distance between force and the resistance

Question 35

what do 3rd class levers do?

Answer 35

increase the speed and ROM at the end on the lever SPEED MULTILIERS so have a mechanical advantage of less than 1 - increase the length of the resistance arm enabling the athelete the increase ROM at the end of the lever therefore increasing the speed/velocity at the end of the lever - thisallows for greater linear velocityto be transferred to objects upon contact achieveing increased speed/distance - the longer the resistance arm, the greater the inertia that needs to be overcome.

Question 36

example of a 3rd class lever is a soccer kick. explain

Answer 36

- decreasing the moment of inertia and resistance arm enables the leg to be swung through more quickly with greater angular velocity. - increasing the length of the resistance arm increases the ROM at the end of the lever, Ball will travel with greater linear velocity.

Question 37

distance | definition

Answer 37

path travelled by an object from start to finish, regardless of the direction travelled

Question 38

displacement | definition

Answer 38

change in position of an object from the starting position to the finishing position

Question 39

speed | def and equation

Answer 39

time taken to cover a certain distance m/s - speed = distance/time