biomechanics Flashcards
newton’s first law of inertia
An object stays in a constant state of motion (moving at same velocity = constant velocity = inertia) unless acted upon by an external force
inertia
inertia = current state of motion = resistance an object has to change its state of motion = the larger the object or greater the mass of the object, the greater the inertia
· E.g. a golf ball will remain stationary on a tee with gravity acting upon it, until the golf club applies an external force to it = greater force, force is greater than gravity and mass of ball so it travels to hole
· If an object is at rest, it will remain still
· If it’s moving in one direction it will continue to do so at the same velocity until another force is exerted upon it
example of inertia
· The bigger the mass, the larger inertia of a body or an object = more force will be needed to change it state of motion
· E.g. easier to stop a 75kg player in rugby union than a 100kg player as they have less resistance
example of newton’s first law
E.g. someone kicking a rugby ball = constant state = ball in still, external force from kick + ball is moving = stays stationary until the rugby player kicks it
newton’s second law of acceleration
an object will accelerate in the same direction as the force applied upon it, and the amount of acceleration is directly proportional to the size of the force
· Force = mass x acceleration
· the quantity of the motion = momentum = acceleration is proportional to the size of the force applied
example of newton’s second law
· Kicks it more hard, moves faster = kicks if softer, moves slower
· E.g. netball = more force in pass, ball travels faster + further = less force in pass, ball travels slower + shorter distance
· E.g. the harder the golfer hits the ball + larger the mass of the club = further the ball will travel
The magnitude (size) and direction of the force applied to a body determine the magnitude + direction of the acceleration given to a body
· E.g. a tennis player will impart. A large force on the ball so it accelerates over the net in the direction which the force has been applied = exerts a large force to the right, ball will travel to the right
newton’s third law of reaction
for every action there is an equal and opposite reaction
describe how newton’s first law applies to the sporting action of a penalty in football
law of inertia:
The ball will remain at rest on the penalty spot, until a force is applied upon it from the boot of the footballer. The football will continue to travel in the direction that it was kicked until another force is applied to it (goalkeeper, hitting the net or post).
describe how newton’s second law applies to the sporting action of a penalty in football
law of acceleration:
The greater the force applied by the footballer, the greater the acceleration of the ball.
describe how newton’s third law applies to the sporting action of a penalty in football
law of reaction:
The foot of the footballer will apply a force to the ball, and the ball will provide an equal and opposite reaction force to the foot of the footballer. If the ball hits the cross-bar, an equal and opposite force is applied by the cross-bar to the ball, resulting in an equal and opposite reaction (the ball bouncing back off the cross-bar).
describe how newton’s first law applies to the sporting action of a chest pass in netball
law of inertia:
The ball will remain at rest in the player’s hands until a force is applied by the hands as it pushes the ball. The netball will continue to travel in the direction that it was pushed in until another force is applied to it (another player catching it and passing/pushing in a different direction) (a defender deflecting/ intercepting the ball, changing the course of its travel/ direction)
describe how newton’s second law applies to the sporting action of a chest pass in netball
law of acceleration:
The greater the force applied by the netball player, the greater the acceleration of the netball.
describe how newton’s third law applies to the sporting action of a chest pass in netball
law of reaction:
The hands of the netballer will apply a force to the ball and the ball will provide an equal and opposite reaction force to the hands of the netballer. If the netball is caught by another player, an equal and opposite force is applied by the hands of the other netball player, to the ball, resulting in an equal and opposite reaction (the ball being pushed/ passed by the player)
describe how newton’s first law applies to the sporting action of putting the ball in golf
law of inertia:
The ball will remain at rest on the tee, until a force is applied by the golf club of the golfer. The golf ball will continue to travel in the direction it was hit until another is applied to it (hitting the ground/ flag pole/post)
describe how newton’s second law applies to the sporting action of putting the ball in golf
law of acceleration:
The greater the force applied by the golfer, the greater the acceleration of the golf ball.
describe how newton’s third law applies to the sporting action of a putting the ball in golf
law of reaction:
The face of the golf club will apply a force to the golf ball and the ball will provide an equal and opposite reaction force to the golf club. If the ball is hit again, an equal and opposite force is applied, to the ball, by the golf club again, resulting in an equal and opposite reaction. OR if the ball bounces (the ground applies an equal and opposite force to the ball).
describe how newton’s first law applies to the sporting action of pushing off the blocks in sprinting
They remain at rest before the gun goes off. They will remain still and at rest until a force is applied on them from their muscles. The athlete will continue to travel in the direction they set off at unless another force is applied on to them (hitting the padding at the end of a race
describe how newton’s second law applies to the sporting action of pushing off the blocks in sprinting
The greater the force applied by the sprinters muscle the greater their acceleration would be
