chapter 4 biomechanical principle Flashcards
Define kinetics
it is motion and the forces or factors influencing it
Define types of motion
it is the body’s change in position in relation to time. Motion can be linear or angular.
explain linear motion (also known as translation)
occurs either in a
straight line or curved path.
- movement in a straight line is referred to as rectilinear motion.
- Movement in a straight line is referred to as rectilinear
motion, where all parts of a body travel the same distance, in the same direction, at
the same time. (e.g. a young child sledding down a mountain on a toboggan)
-Movement over a curved path
is referred to as curvilinear motion (e.g. the path of a ball thrown through the air until gravity forces it to the
ground).
Define angular Motion (referred to as rotation)
takes place when a
body moves along a circular path
-occurs when a body moves along a circular path at the same angle, in the same direction, at the same time.
-Angular motion occurs around some type of axis, which can be either external or internal.
-An example of an external axis in sport is a gymnast rotating around a high bar,
while an internal axis would be a joint in the body around which a body part rotates
Define General Motion
the combination of
linear and angular motion
example- is the running in a straight line seen in a 100-metre sprint
caused by the angular rotation of the arms and legs
define Mass
- the quantity of matter found within a particular body.
-typically measured in kg
-Person with large mass is composed of large quantities of matter
-Person with small mass is composed of small quantity of matter.
Define Inertia
the reluctance of a body to change its state of motion.
- linked to an object’s body mass.
- a body at rest may be reluctant to move, and a body that is moving may be reluctant to stop.
Define Force
A push or pull.
- to change the state of a body a force must be applied to it that causes it to accelerate, decelerate or change direction.
Formula for Force
F=ma (force= mass x acceleration)
Define distance
The length of space between two points.
- the amount of ground an object covers throughout its monition
example- a runner completing 800m on an athletics track the total distance is 800m
Define Displacement
the difference between the initial position and final position of an object
-object’s overall change of position from one point in time to another.
example- runner completing 800m on an athletics track total displacement is 0
Define Linear Speed
the rate of motion
distance/time
Formula for speed
Speed=distance/time
s=l/t
Define Velocity
The rate of the speed at which an object moves its position
Velocity formula
Velocity = Displacement/ Time
V=d/t
Example for speed and velocity
- a runner starts at the beginning of a straight 600m road north and finishes 600m away in 90 seconds
speed = d/t= 600/90=6.6m/s
Define Linear Acceleration
the rate of velocity change experienced by an object over time
Formuls for acceleration
acceleration= final velocity- initial velocity/ time
a=Vf-Vi/t
Define Momentum
The quantity of motion a particular body of mas has. It is the product of mass and velocity.
Formula for Momentum
Momentum (p) = mass (m) x velocity (v)
Example of momentum
The tee ball has mass but because it is stationary it has zero velocity. the batter in tee ball, who is trying to hit a home run, will strike the ball with as much force as possible. this force will increase the velocity of the ball giving it momentum. the objective is to maximise momentum so that the ball travels as far as possible.
Define Conservation Of Momentum
Whenever 2 bodies collide their combined momentum is conserved.
When 2 objects collide the momentum of both objects when combined are the same pre and post collision
Example of conservation of momentum
Player A is running with the ball, player B is coming in for the tackle. As they collide, their combined momentum is conserved. The velocity changes for both players impact but the momentum is less now.
Define Force summation (of momentum)
The correct timing and sequencing of body parts to produce maximal force.
-It is particularly important in sports where the objective is to throw, hit or kick an object or ball as far as possible, such as in javelin, discus, soccer or baseball.
Simultaneous force summation
Generating maximum force by simultaneously coordinating and activating multiple body parts.
All relevant body parts contribute force simultaneously to generate power and efficiency in movement’s like a basketball pass
Impulse and formula
The change in momentum
Impulse= Force x time
