biomechanics Flashcards
State Newton’s first law
Law of inertia: A body will remain in a state of rest or constant motion unless acted upon by an external or unbalanced force
State Newton’s second law
Law of acceleration: A body’s rate of change in momentum is proportional to the force applied to it and acts in the same direction of the force applied.
State Newton’s third law
Law of reaction: For every action force applied to a body there is an equal and opposite reaction force.
Give one practical example of Newton’s first law while including the definition of the law
An example of inertia is a cricket bat will remain at rest in the batters hand until an unbalanced force is applied through the batters arm to move the bat in order to hit the ball.
Give one practical example of Newton’s second law while including the definition of the law
An example of acceleration is in cricket, the more force that the bowler applies to its bowl, the quicker the balls rate of change in momentum will be and will move in the direction the force is applied.
Give one practical example of Newton’s third law while including the definition of the law
When the bat hits the ball in cricket the ball applies a force onto the bat and the bat applies an equal and opposite force back onto the ball.
Draw a free body diagram of a sportsperson accelerating
free body diagram of a sportsperson decelerating
free body diagram of a sportsperson about to gain flight
free body diagram of an object in flight
describe the four forces shown in a free body diagram
Weight is the effectiveness of a gravitational field on a mass.
Air resistance is the force that opposes a horizontal motion of a body whilst moving through the air.
Ground reaction force is the amount of force applied by the ground onto the body in contact with it.
Friction is a force that opposes motion between two forces that are in contact.
What is a body’s COM
A body’s centre of mass is the point at which the body’s weight is distributed evenly in all directions
Explain the factors that affect air resistance
Velocity of the body (the faster the body is, the greater the air resistance.)
Cross-sectional area ( the greater the cross-sectional area the greater the air resistance.)
Shape of object( pointy shaped objects cut through air resistance more easily, for example, an F1 car or the tear drop shape of a track cyclists helmet.)
type of surface (a rough surface will create more air resistance or drag than a smooth surface. te dimples in a golf ball reduce its air resistance)
Explain the factors that affect friction
roughness of the ground surface, roughness of contact surface, temperature and size of normal reaction
What is streamlining
The creation of smooth air flow around an aerodynamic shape to minimise air resistance
what shapes are used to minimise AR?
tear drop and aerofoil
How does size of normal reaction affect friction
increase = more friction e.g. a shot putter with a large mass will have greater friction in the throwing circle helping prevent over rotation
How can force plates be used to improve performance
Force plates can be used to measure ground reaction force. This can be used to prevent injury as it measures the size and direction of forces acting back onto athlete. force plates Can be used for balancing jumping and running. It can be used for sports biomechanical assessment, gait analysis, rehabilitation and physical therapy.
how can wind tunnels be used to improve an athletes performance
Wind tunnels are large tunnels with air blowing through used to replicate wind blowing into an object. Use of coloured smoke is used to see how air interacts with object. This increases an atheletes performance as the aim is to improve flow of air around the object, reduce drag, increase lift and improve streamlining
Strengths and weaknesses of using limb kinematics to improve performance
strength- Results are immediate.
it can focus on specific body parts and phases of the skill.
Weakness- low reliability as markers are not easily replicable.
doesn’t allow room for individual differences in human anatomy.
What is meant by effort arm
the distance between the point of the application of effort and the fulcrum, usually where the muscle attaches to the bone
what is meant by the load arm
the distance between the point of resistance or load and the fulcrum.
Where would you find a class 1 lever system
neck (tilting head back), elbow
where would you find class 2 lever system
role of the gastrocnemius and soleus in calf raises. (gastrocnemius, bone, balls of feet)
