Biomechanics Flashcards
Biomechanics
Science that studies living things from a mehcanical perspective, that can help develop and refine human movement.
Quantitative movement analysis
uses numerical data to assess human movement (how fast - stop-watch)
Force
A push or a pull. Can change the shape, move the object or alter movement of the object.
Force =
mass x acceleration (Newtons)
Type of force
friction, gravitational force, drag force and weight
Friction
a force that occurs when two surfaces come in contact with each other. Opposes motion. (curling: smooth ice out, reduces friction, so stone travels faster)
Two types of frictional forces
Gravitational and drag force
Drag force (air and water)
A frictional force when one surface is air or water, that opposes direction of motion of an object (slowing it down).
As speed increases…
drag increases.
Gravitational force
a frictional force of attraction between two objects. On Earth, objects fall downward toward the centre of Earth. (is constant until drag force effects)
Acceleration due to gravity
9.8m/s^2
Weight
the force exerted on the body by gravity.
Weight =
mass x gravity (Newtons)
Mass
amount of matter in an object (kg).
Greater the mass…
greater the inertia.
Inertia
tendency for body to resist/oppose change in its state of motion (what keeps you going) (medicine ball has greater inertia than volleyball)
Momentum
“mass in motion (on the move) “ The quantitiy of motion on the body (force or speed of movement) The greater momentum, harder it is to stop.
Momentum =
mass (kg) x velocity (m/s) (kgm/s)
Two objects with the same mass but different velocities…
( one object should ) increase velocity to increase momentum.
Two objects with the same velocities but different masses
object with greater mass, will have greater momentum (can’t change mass of an object)
A collision between two objects…
both will move in the direction of the object with the greatest momentum.
Conservation of momentum (Mv = mV)
Total momentum before collision = total momentum after collision.
Summation of momentum
Sequential, coordinated movement of each body segment at the same time to generate force. (throwing a tennis ball with wrist, shoulder, trunk will go further than throwing with just your wrist)
BEST summation of momentum
Use as many Body parts as possible, sEquence move the heavier body parts first then the lighter, body parts must be Stable so momentum is not lost and move the next body part when the previous body part has reached maximum velocity.
Impulse
The amount of time at which the force is applied.
The change in momentum of an object. To change momentum, a force must be applied over a period of time
Impulse =
force x time
Impulse example
a softball struck with a large force, the ball is in contact with the bat for a fraction of a second. Compared to, a golf ball rolling along a putting green until it comes to an eventual stop. This is a small force applied over a greater period of time. But both experience a change in momentum.
How can impulse be manipulated?
by increasing or decreasing the velocity of an object. (an increase in time over which the force is applied, will result in a greater impulse being applied and a greater release velcoity of the shot in shot put)
Linear Distance
path travelled from start to finish.
Linear Displacement
change in position of object from start to finish.
Linear Speed
Time taken to cover distance. Speed = distance / time
Linear Velocity
How quickly an object changes it’s position. Velocity = displacement / time