3.1/3.2 - Biomechanical principles Flashcards
What is Newtons first law?
Law of inertia
What is the law of inertia?
A body continues in a state of rest or uniform velocity unless acted upon by a external or unbalanced force
What is inertia?
The resistance of a body to change its state of motion
What is inertia?
The resistance of a body to change its state of motion
What is newtons 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 way.
What is momentum? (kgm/s)
Mass x Velocity
What is newtons third law?
Law of reaction
What is the law of reaction?
every action force applied to a body there is an equal and opposite reaction force.
What is acceleration? (m/s/s)
(final velocity - initial velocity) / time
What is velocity? (m/s)
displacement / time taken
What is force?
Mass x acceleration
What is an internal force?
a force generated by the contraction of skeletal muscles
What is an external force?
a force that comes from outside the body and acts upon it e.g. air resistance
What is net force?
The sum of all of the forces acting on a body. If net force = 0 then the body is in balance
What is a free body diagram?
A labelled sketch showing all of the forces acting on a body at a particular time
What are the 4 forces that are always labelled on a free body diagram?
Weight, Reaction, Friction, Air resistance.
What is the centre of mass?
The point at which a body is balanced in all directions
What is stability?
The ability of a body to resist motion and remain at rest
What factors affect stability?
Mass of the body, height of the centre of mass, base of support, line of gravity
What are the components of a lever?
Fulcrum, Effort, Load
What is the structure of a 1st class lever?
effort and load are either side of the fulcrum which is in the middle e.g. extension of neck when preparing for a header in football.
What is a second class lever?
effort and fulcrum are either side of the load which is in the middle e.g. ball of foot in high jump take off.
What is a third class lever?
load and fulcrum are either side of the effort which is in the middle e.g. elbow in bicep curl
What lever gives mechanical advantage?
second class lever systems where the effort arm is greater than the load arm
What lever gives mechanical disadvantage?
third class lever systems where the load arm is greater than the effort arm.
