Biomechanics - Kinetic Linear Concepts (Unit 3 AOS 1 Terms) Flashcards
56 List 2 sporting situations where it is an advantage to decrease the friction?
LINEAR CONCEPTS
Swimming by wearing a speed suit (black tight suit)
cycling - tight fitted clothes
- narrow tires
means less surface
area and less
friction
Water skiing
road cycling
ice skating
List 2 situations where it is an advantage to increase friction?
LINEAR CONCEPTS
basketball = changing directions with shoes - friction between shoes and floor
Spikes, applying chalk, gloves, waxing surfboard
In order to move an object across a surface, you must overcome the friction. How would you achieve this?
LINEAR CONCEPTS
Increasing the force applied
Mass
LINEAR CONCEPTS
A measure of the amount of matter an object is made up of (measure in kg)
is constant (doesnt change)
+++use mass more in biomechanics+++
Weight
LINEAR CONCEPTS
The force that is exerted on the body by gravity
more force needs to be produced to move an object of greater weight
link between mass and inertia
LINEAR CONCEPTS
The greater the mass the greater the inertia.
Inertia and force tip
LINEAR CONCEPTS
The force applied to the object must be greater than the inertia of the object in order for the motion to change. I.e. you need sufficient force to overcome inertia
Speed
LINEAR CONCEPTS
distance / time (how quickly an object covers distance)
from a to b
Velocity
LINEAR CONCEPTS
displacement / time
(the rate of change in an object’s position in a specific time range.)
Momentum has a key role in collision - what is this role?
LINEAR CONCEPTS
At collision there is a change in momentum. MASS doesn’t change, so there must be a change in velocity.
example - Conservation of momentum (linear)
LINEAR CONCEPTS - stick and ball
Before collision:
Ball possesses zero momentum as it is not moving
Stick possesses momentum equal to its mass x velocity (swing)
After collision:
Stick possess zero momentum as it stops after the hit
The ball possess momentum equal to its mass x velocity (ball flying away)
As momentum is the same (conserved), due to the ball having less mass than the stick, it will travel at a greater velocity than the speed of the stick prior to hitting (swing speed).
This is why the ball ‘flies’ off the stick when hit.
Conservation of momentum (linear) - what is it? and example
LINEAR CONCEPTS
The total momentum of the system before the collision is equal to the momentum after the collision.
eg: release of a javlon
eg2: 10 pin bowling
objects in the system include bowling ball and pin
some momentum from the ball tranfers to th pins
Summation of momentum what body parts,
and examples
LINEAR CONCEPTS
The correct timing and sequencing of body segments and muscles through a range of motion to produce maximum force.
adding together body parts from heaviest and largest to lightest smallest
PRODUCES MAXIMUM FORCE FOR MAXIMAL FORCE ACTIVITIES INCLUDING:
eg:
wight lift
shot put
3 pointer
long kick in footy
two types of summation of force
LINEAR CONCEPTS
- Simultaneous Force
- Sequential Force
Simultaneous Force
(summatation of force)
LINEAR CONCEPTS
Summation - body parts move at the same time to perform the action eg. 100m sprint
Sequential Force
(summatation of force)
LINEAR CONCEPTS
Summation- body parts move in a sequence to produce the desired degree of force.
IMPULSE def and equation and what must you do to change the momentum of an object?
The greater…
LINEAR CONCEPTS
change in momentum of the object.
Impulse = force x time
to change the momentum of an object, force must be apllied over a period of time - the greater the impulse, the greater the change in momentum
Impulse can be manipulated by…
LINEAR CONCEPTS
- increasing the time the force is being applied
- applying greater force.
- Maximimising time AND force
how can impulse be manipulated to increase velocity of an object- discuss example
LINEAR CONCEPTS
Increasing time (eg. arm back before throwing and release forwards and flick fingers)
Throwing techniques e.g discuss (2.22 p47)
Run-up (increasing time).
Longer stride length
how can impulse be manipulated to decrease velocity of an object - examples
LINEAR CONCEPTS
Breaks in a car
Motorbike landing
Protective gear (catcher’s glove)
Cradling a ball when catching
how to answer an impulse question using deep eg with tennis player
LINEAR CONCEPTS
D- Impulse is the change in momentum of an object
E- It is calculated by force x time
E- By having a greater follow through in his second serve, the player was
applying the force onto the ball for a greater period of time.
P- This will mean there was a greater change in momentum of the
ball, and the reason it went 30m further than the serve with no
follow through.
what is DEEP?
Definition
Equation or diagram
Example
Performance. How does it affect performance?
Newtons first law of motion (DEEP)
LINEAR CONCEPTS
The Law of Inertia
Definition:
an object will remain at rest or in its current state of motion unless acted upon by an external force (such as gravity)
Equation or diagram:
NA
Example:
Objects want to continue doing whatever it is they are doing! They will only change their state if there is an unbalanced force put on the object - by doing this, you are overcoming the inertia of the object
Performance:
If something is heavier then it is going to need a bigger force to overcome its current state (whether moving or still)
Newton’s second Law
LINEAR CONCEPTS
The Law of Acceleration
equation:
Force = Mass x Acceleration
Definition:
A force applied to an object will produce a change in motion (acceleration) in the direction of the applied force that is directly proportional to the size of the force and inversely proportional to its mass.
Simply:
Inversely proportional to its mass means the bigger the mass, the less of an acceleration it will have
More force = more acceleration = further/faster the object will go in direction force is applied
Less mass = more acceleration if the same force is applied.
F
M A
Newton’s Third Law
LINEAR CONCEPTS
The Law of Action-Reaction
Definition: For every action, there is an equal and opposite reaction
Forces always work in pairs.
When two forces come into contact with one another, they exert forces that are equal in size but opposite in direction on each other.
Where is the action-reaction occuring when someone is running?
LINEAR CONCEPTS
Between her feet and the ground
The action of the arms and legs
Pairs of muscles
LINEAR CONCEPTS
Newton’s three laws of motion
Inertia
Mass
Force
Momentum (Conservation of momentum, summation of momentum)
Impulse
Difference (definitions) between linear and angular motion
ANGULAR CONCEPTS
Linear motion:
The motion of a body along a straight or curved path
Angular motion:
movement around an axis (internal or external).
Caused by an eccentric force
Internal Axis (Joints)
External Axis (Parallel bars)
Force
Force is the product of mass and acceleration
A force can have either a pushing or pulling effect on a body with mass.
All forces produce or change movement.
Forces cause objects to accelerate (speed up, slow down or change direction)
what are the external Forces (push or pull)
Types of forces
LINEAR CONCEPTS
Friction
Air and water resistance
Gravitational force (gravity)
Weight
These forces cause objects to speed up, slow down or change direction
Internal Forces
Types of forces
LINEAR CONCEPTS
Skeletal forces
Friction
LINEAR CONCEPTS
When 2 surfaces come into contact with one another.
Friction opposes the motion of an object.
How is force calculated?
LINEAR CONCEPTS
FORCE = MASS X ACCELERATION
the unit of measurement is the Newton.
A Newton is the amount of force required to accelerate 1kg of mass at 1 m/s2
Air and water resisitance
LINEAR CONCEPTS
object moves through air or water experiencing drag force
drag force oppose the direction of motion of the object, slowing it down
what could effect the amount of drag experienced by an athlete?
And how could an athlete minimise these things?
LINEAR CONCEPTS
- density
- cross sectional area
more = more drag force
less = less drag force - speed of object
technique
clothing
design of equiptment (decrease drag and corss sectional area and make the athlete more streamline
gravitational force
LINEAR CONCEPTS
force of attraction betweem two bodies or objects
its a pull force
do not use mass and weight ____________?
LINEAR CONCEPTS
do not use mass and weight interchangeably
When needing to write which forces are applied in a certain sporting example, there will always be__________ and _________ present.
LINEAR CONCEPTS
internal forces of muscles = muscles pull
gravitational force
Inertia
LINEAR CONCEPTS
An object will remain at rest or in constant motion unless acted upon by an external force
resisitace of a body to change its state of motion
what is static inertia?
What is dynamic Inertia?
LINEAR CONCEPTS
static:
reluctancy to move
eg:
100Kg barbell
dynamic:
reluctant to stop
Force and inertia
LINEAR CONCEPTS
force applied to the object must be greater than the inertia of the object in order for the motiom to change
linear momentum and equation
LINEAR CONCEPT
the amount of motion an object has and its resisitance to changing that motion
momentum is mass x velocity
what is the momentum of an object that is not moving?
LINEAR CONCEPTS
zero velocity = zero momentum
Momentum v impulse
How is momentum different to inertia?
LINEAR CONCEPTS
A stationary object has inertia but not momentum
Momentum V Impulse
How can you change an object’s momentum?
larger the force….
LINEAR CONCEPTS
Apply a force – the larger the force the greater the change in momentum.
Impulse
How could you improve a cricketer’s throwing technique to make them throw the ball further?
LINEAR CONCEPTS
arm back - force is applied over a longer period of time therefore more momentum when ball is let go therefore, impulse was manipulated
the cricketer can then increase the time over which the force is applied
Reducing Impulse
LINEAR CONCEPTS
decreasing momentum = when a ball is coming towards you, you can cup the ball and move your hands back while catching the ball, increasing the time over which the force is applied therefore decreasing momentum
equations
1. force
2. momentum
3. Impulse
4. Moment of Inertia
5. Angular momentum
6. Change in momentum = change in impulse
7. torque
Force = Mass x acceleration
Momentum = Mass (kg) x velocity (m/s)
- same as (p = mv)
Impulse = force x time
- same as (I = Ft)
Moment of Inertia = mass x radius2
Angular momentum = moment of inertia x velocity
- if moment of inertia increases, angular velocity decreases and vice versa to keep angular momentum the same
Change in momentum = change in impulse (△Ft = △mv)
Torque = force x distance from axis of rotation
