Biomechanical Principles Flashcards
What is a force?
A push, pull or twist that alters the state of motion of the body
What is a body?
An object that a force is applied to
What is Newton’s first law?
The law of inertia
What is the law of inertia?
‘A body continues in a state of rest or terminal velocity unless acted upon by an external or unbalanced force’
What is inertia?
The resistance of a body to change its state of motion
What does a greater mass mean in relation to inertia?
Greater inertia
What is Newton’s second law?
Law of acceleration
What is the law of acceleration?
‘A body’s rate of change in momentum is proportional to the size of the force applied and acts in the same direction as the force applied’
What is Newton’s third law?
Law of reaction
What is the law of reaction?
‘For every force applied to a body there is an equal and opposite reaction force’
What is an action force?
The force generated by the athlete to the ground or object
What is a reaction force?
An equal and opposite force generated by the ground or object back to the athlete
What is velocity?
The rate of change in displacement
How is displacement calculated?
The shortest line - the line route
(between start and finish)
How is velocity calculated?
Velocity = displacement/time
What is momentum?
Momentum is the quantity of motion possessed by a moving body
How is momentum calculated?
Momentum = mass x velocity
What is acceleration?
The rate of change in velocity
How is acceleration calculated?
Acceleration = change in velocity/time taken
How is change in velocity calculated?
Change in velocity = final velocity - initial velocity
How is force calculated?
Force = mass x acceleration
F = ma
What is an internal force?
A force generated by the contraction of skeletal muscles
What is an external force?
A force generated from outside the body that acts on the body
What are the 5 effects of force?
- create motion
- accelerate a body
- decelerate a body
- change the direction of a body
- change the shape of a body
What is a vertical force?
A force that pushes a body up or pulls a body down
What is a reaction force?
A force that is equal and opposite to the force applied in the first instance
What is weight (as a force)?
A force that pushes a body down
What is a horizontal force?
A force that either pushes a body forwards or pulls a body back?
What is friction?
A force that pushes a body forwards; and opposes the motion of two surfaces in contact
What is air resistance?
A force that pulls a body back; and opposes the body moving forwards
What are positive forces?
Friction and reaction
What are negative forces?
Air resistance and weight
What is the net force?
The overall motion of the body when all forces are considered
What does it mean if the net force is zero?
All forces are balanced and the body its either at rest or at terminal velocity
How is weight calculated?
Weight = mass x acceleration force of gravity
What does gravity do?
Pulls on the centre of mass
When is a reaction force present?
When two bodies make contact; it is equal and opposite to weight
What is friction affected by?
- roughness of surface
- temperature
- size of normal reaction
What is air resistance affected by?
- velocity
- shape
- frontal cross-sectional area
- smoothness of surface
What is the centre of mass?
All forces are balanced in all directions
What is the ‘Fosbury Flop’?
A high jump technique where the centre of mass moved outside of the body
What is stability?
The ability for a body to resist motion and remain at rest
What affects stability?
- mass of body
- height of centre of mass
- line of gravity
