Chapter 3 - kinetic Concepts Of Human Movement Flashcards
What is Biomechanics
Study of living things from a mechanical perspective. The physics of human movement
Kinetics
The study of forces that cause motion. (Torque, gravity, friction etc)
Quantitative movement analysis
Looks at numerical data, (height, weight, mass, speed, distance, etc)
Qualitative analysis
A description of the performance, (based on opinion)
Force
A push or pull which alters that state of motion of a body
Force=mass x acceleration
2 ways force affects an object
- Changes the shape of an object, (stretching, squashing or twisting)
- Moves the object, (speeds up or slows down, changes direction)
Friction
- occurs when 2 surfaces come into contact with each other
- opposes the motion of an object and can be increased or decreased
Drag (air and water resistance)
- when an object moves through air and water it experiences a drag force
- drag forces oppose the direction of motion of the object, slowing it down
Gravitational force
On earth gravitational force is the force that causes objects to fall downwards towards the centre of the earth
Mass
A measure of the amount of matter an object is made of
Weight
- the force that is exerted on a body by gravity
Weight = mass x gravity
Inertia
Objects at rest or in motion will continue to be in the same state unless acted upon by an external force
Eg, the greater the weight of an object, the greater the inertia
Momentum
The measure of the amount of motion a body or object has
Momentum = mass (Kg) x velocity (m/s)
Conservation of momentum
The total momentum of the body before the collision is equal to the total momentum after the collision
Summation of momentum
The transfer of momentum from the larger, slower moving part to the smaller, faster moving parts to maximise the release of an object
Impulse
Is equal to the change in momentum of an object. To change the momentum of an object, a force must be applied over a period of time
- impulse = force x time
Newton’s first law of motion
An object not change its motion unless acted upon by an external force
Newton’s second law of motion
A force applied to an object will produce a proportional acceleration to the size of the force it was acted upon
Newton’s 3rd law of motion
For every action there is an equal and opposite reaction
Newton’s first law of angular motion
The angular momentum of a body remains the same unless acted upon by an external torque
Second law of angular motion
A torque applied to an object will produce a proportional acceleration to the size of the torque it was acted upon
3rd law of angular motion
For every torque there is an equal and opposite torque
What is a torque
A measure of how much a force acts in an object causing that object to rotate
Angular motion
The product of the moment of inertia and angular velocity rotating a rounding an axis
Angular momentum = moment of inertia x angular velocity
Moment of inertia
The resistance of an object to changes in angular momentum
