Kinetics

• Angular Momentum

  • refers to the quality of angular motion possessed by a rotating body
• Motion Of Inertia

  • refers to the resistance of a rotating object to change its state of motion
• Angular Velocity

  • the quantity of angular motion possessed by a rotating body
• Angular momentum = motion of inertia X angular velocity
• Biomechanics


  the study of motion and movement
• Benefits of Biomechanics

  • technique efficiency
  • injury reduction
  • modification of sport equipment to improve sport performance
• Kinetics


  the branch of mechanics that deals with the actions of force in producing or changing the motion of masses
• Momentum


  The amount of motion possessed by a moving body
• Momentum = Mass (kg) X Velocity (m/s)
• The greater its movement, the more force that needs to be applied to either stop or slow the object down
• Impulse


  The application of force over a period of time to change the movement of an object (change in momentum of an object)
• Impulse = force X time
• Force = Mass X Acceleration and Time
• Impulse Can Cause

  1. impulse can create momentum
  2. changes momentum
  3. stopping momentum
• Conservation Of Linear Movement 


  the total movement of two objects before and after impact are equal
• Energy Can Be Lost To Collision

  • sound
  • heat
  • change in shape
• Impact Is Determined By Following Variables

  • mass
  • velocity
  • mass and ability of athlete
  • contact with sweet spot
  • elasticity of ball
• Elasticity


  the ability of an object to return to its original shape after being deformed
• Coefficient Of Restitution


  measures the elasticity of the collision between an object and given surface
• A coefficient of restitution of 1 represents a perfectly elastic collision
• a coefficient of restitution between 0 & 1 is an imperfectly elastic collision
• a coefficient of restitution of 0 represent a perfectly inelastic collision
• Perfectly Elastic Collision


  when a ball is dropped from a given height the ball will rebound to that same height after colliding with the ground
• Perfectly Inelastic Collision


  when the ball is dropped and it doesn't bounce at all
• Imperfectly Elastic Collision


  when a ball is dropped from a given height the ball will rebound some of the way up but it will not reach the height it was dropped from
• Factors That Affect COR

  • equipment and surface
  • temperature of the balls
  • velocity of the collision
• Conservation of Angular Momentum


  states that when no external torque acts on an object, no change of angular momentum will occur
• Levers

  • fulcrum
  • resistance
  • effort
• Fulcrum/Axis


  the point around which the lever rotates
• Input Force/Effort


  force exerted on the lever
• Output Force/Resistance


  force exerted by the lever
• Mechanical Functions Of Levers

  1. increase application of force - E longer than R
  2. increase speed of movement - E shorter than R
• First Class


  fulcrum in the middle
• Second Class


  resistance in the middle
• Third Class


  effort in the middle\
• Factors Affecting The Use Of Levers

  1. length of lever
  2. the interim of the lever
  3. the amount of force
• Balence 


  the ability to neutralise forces that distribut equilibrium
• Factors That Affect Balance

  • size of base of support
  • height of the centre of gravity
  • position of the line of gravity
  • mass of the object
• Centre Of Gravity


  the theoretical point in an object, located either inside or outside of the body, where all of the body's mass is equally distributed
• Line Of Gravity


  the line of gravity is an imaginary vertical line passing downwards from then centre of gravity to the ground or surface the person is on