3.1 Biomechanics Flashcards
What is netowns first law of motion?
Inertia – states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force. It is the reluctance of a body to change its state of motion
What is newtons second law of motion?
- Acceleration of a body is proportional to the force causing it and the acceleration takes place in the direction in which the force acts
- F=ma
What is scaler motion?
no direction but movement
What is vector motion?
direction and movement
What is newtons third law of motion?
- When one object exerts a force on a second object, there is an equal and opposite force exerted by the second object on the first
- For every action there is an equal and opposite action
What are all the vertical forces?
- gravity
- reaction force
What is reaction force?
where the points of contact are
Where is gravity acting from?
center of mass
What are the horizontal forces
air resistance
friction
WHere does friction act from
point of contact
Where does air resistance acto from?
center of mass to behind you
What is linear motion?
straight line
What is angular motion?
rotation about a particular point (axis of rotation)
What is general motion?
rotation and straight line motion
What is velocity?
rate of change in displacement
WHat is the velocity equation?
displacement / time taken
What is momentum?
quantity of motion possessed by a moving body
What is momentum equation?
mass x velocity
What is acceleration?
rate of change in velocity a
acceleration equation?
(final velocity - initial velocity) / time taken
What is force
push or pull that alters the state of motion of a body
How do you calculate force?
mass x acceleration
What is net force (resultant force) ?
the sum of all forces acting on the body
What is reaction?
the equal and opposite force exerted by a body in responce to the action force placed upon it
Force causes a moving body to?
- change direction
- Accelerate
- Decelerate
What is the centre or mass?
the point at which the body is balanced in all directions, or where all the mass could be considered to be concentrated
What is the center or mass continuously doing?
changing
What is stability?
the ability of a body to resist motion and remain at rest
What are the factors effecting stability?
- mass of the body
- height of the center or mass
- base of support
- line of gravity
How is the fosbury flop beneficial?
- uses j curve to allow greater velocity
- plants outside leg to allow inside leg to lift, along with arms, at take off to raise the center of mass as high as possible
- fully extends spine to rotate around the bar moving the center of mass outside of the body and below the bar. Only one section of body has to be above the bar at one time.
( center of mass passes underneath the bar, fosbury flop requires less take off force to clear the same height as earlier techniques . when maximum force is generated at take-off greater heights can be achieved.)