Biomechanics Flashcards
(31 cards)
Definition of force
The action causing the load to move
Definition of a fulcrum.
An axis or pivot point
Eg elbow
Definition of a lever
A rigid bar resting on a pivot, used to move fixed load when force is applied to the other side
In relation to lever length. Explain what happens when force increases
Force arm length increases
Resistance arm length decrease
In relation to Lever length. Explain what happens when there is an increase In speed
Force arm length decreases
Resistance arm length increase
Explain Class 1 lever with example
Axis is between resistance point & force application magnifies force applied.
Eg Head & Neck
Explain a 2nd class lever with example
Axis is at the end of the lever and the resistance is between the axis and force.
Eg wheelbarrow
Explain a class three lever include an example
Axis is at the end of the lever and the force is applied between the axis and resistance.
Eg most muscles
Explain a Concentric contraction
Muscle gets shorter
Forces decreases as the velocity of shortening increase
Explain an eccentric contraction
Muscle gets longer
The force resistance increases as the velocity of lengthening increases
Newtons 1st law
Inertia- an object at rest tends to stay at rest, until acted upon by another force.
Eg train moving and coming to a stop
Newtons 2nd law
Force & Acceleration, when a body is acted upon by a force it’s resulting change in momentum is proportional to the force changing it.
Newtons 3rd law
Action reaction, for every action there is an equal and opposite reaction whenever one object exerts a force on the 2nd object.
Approaching ball has…
Collision kinetic energy
During impact the ball has…
Elastic potential energy
A rebounding ball has…
Rebound kinetic energy
Explain the coefficient of restitution
Measure of balls liveliness
Ratio of outgoing to incoming speed
Outgoing speed/incoming speed.
During collision what dents?
The ball and the surface it hits
The denting surface…
Stores and returns the energy, in a rebound effect.
Explain moment of inertia
Axis goes through centre of gravity
Once airborne angular momentum doesn’t change because there is nothing to push or pull against
How to divers manipulate moment of inertia?
Tucking, meaning mass is closer to the axis of rotation, less movement of inertia
Define fluid mechanics
The study of forces that develop fluid or air.
2 major fluid resistance are…
Drag or lift
What happens when an object moves through a fluid?
Creates a disturbance to the fluid, the greater the fluid means the greater the transfer of energy from object to fluid.
