The Law of Inertia states A body continues in a state of rest or of uniform velocity unless acted upon by an external unbalanced force.
Newton's second law is the Law of Acceleration.
The Law of Acceleration state A body's rate of change in acceleration or momentum is directly proportional to the size of the force applied and acts in the same direction as the force applied.
Newton's third law is the Law of Reaction.
The Law of Reaction states for every action force applied to a body there is an equal and opposite reaction force.
Newton's first law can be seen in the sprint start as the runner is at rest in the blocks until the blocks provide a force to cause her to overcome inertia and start accelerating.
Newton's second law can be seen in the sprint start as the sprinter's acceleration is directly proportional to the amount of force provided by the blocks and in the same direction.
Newton's third law can be seen in the sprint start as the sprinter applies a force to the blocks, and the block apply an equal and opposite force back to the sprinter.
The role of the centre of mass is crucial to sports performance.
The centre of mass is the point at which the body is balanced and weight is equally distributed.
In the human body, the centre of mass is not a fixed point located in a specific part of the body.
The centre of mass' location will vary depending on the body position.
The centre of mass can also fall outside the body.
The centre of mass follows a predetermined flight path.
We can move the centre off mass around and outside the body to enhance sporting performance.
In the Fosbury flop, the high jumper raises their knee and arms to raise the C of M prior to take off.
During the Fosbury Flop flight, the performer will extend their spin and flex their knees. This moves the C of M outside of the body and below the bar.
The Fosbury Flop technique allows higher heights to be achieved with the same force as previous techniques.
The more stable you are the more you can resist knocks and intimidation through contact sports.
Sometimes it is beneficial to be unstable , like a badminton player wanting to change direction or a gymnast performing sommersault.
There are 4 factors that affect a sportsperson's stability: the position of the centre of mass; position of the line of gravity; base of support; and mass of the athlete.
The lower the COM the more stable the performer.
The higher the COM the less stable the performer.
The line of gravity needs to be over the base of support for increased stability.
If the line of gravity is not over the base of support the athlete will be unstable.
The more contact points you have with the ground and the larger the base of support, the more stable you will be.
Mass can increase stability as it takes more force to move (this is due to inertia).
A force is a push ot pull that alters a state of motion.
Motion is another term for the movement of a body.
For there to be a change in motion a force must be applied. The greater the force the sprinter applies the greater the acceleration.
When all forces are considered the resultant force acting on a body is termed net force.
If there is a net force present the body will be changing its state in motion.
If net force is zero there is no change in motion.
Balanced forces occur when two or more forces acting on a body are equal in size and opposing in direction.
With balanced forces the net force is zero, and the body will remain at rest or in morion at constant speed or uniform velocity.
Unbalanced forces these occur when two forces are unequal in size and opposing direction.
A net force will be present with unbalanced forces and the body will change its state of motion, either accelerating (positive net force) or decelerating (negative net force).
Weight is the gravitational pull that the earth exerts on a body.