biomechanical movement

• linear motion- motion in a straight or curved line with all all body parts moving the same distance at the same speed in the same direction
• inertia- the resistance an object has to a change in its state of motion
• newton first law of inertia- a force is required to change the state of motion of an object
• newtons second law of acceleration- the magnitude and direction of the force determines the magnitude and direction of the acceleration
• force= mass x acceleration
• newtons third law of motion- for every action there is an equal and opposite reaction
• ground reaction force- the equal and opposite force exerted on a performer who applies a muscular force on the ground
• speed= distance/time
• center of mass- the point of concentration of mass, the point of balance of a body
• line of gravity- this is the line extending vertically downwards from the center of mass
• factors affecting stability

  • the height of center of mass
  • position of the line of gravity
  • area of the support base
  • mass of the performer
• fulcrum- the point at which the lever rotates
• resistance- the weight to be moved by the lever system
• effort- the force applied by the lever system
• first class lever

  A) effort

  B) load

  C) fulcrum

  
• second class lever

  A) fulcrum

  B) load

  C) effort

  
• third class lever

  A) fulcrum

  B) effort

  C) load

  
• force arm- the length of the line between the fulcrum and effort
• resistance arm- the length of the line between the fulcrum and resistance
• mechanical advantage- resistance arm is longer than force arm. large load can be moved with small effort
• mechanical disadvantage- force arm is longer than resistance arm. it has a large range of movement
• scalar quantities- size
• vector quantities- size and direction
• mass- the quantity of matter the body possesses
• weight- the gravitational force exerted on ana object
• distance- the path a body takes as it moves from the starting to the finishing position
• displacement- the shortest route in a straight line between the starting and finishing position
• speed- the body's movement per unit of time
• velocity- the rate of change of displacement
• acceleration- the rate of change of velocity
• acceleration= change in velocity/ time
• change in velocity= final velocity- initial velocity/ time
• velocity= displacement/ time taken
• momentum= mass x velocity
• external force- comes from outside the body
• internal force- generated by skeletal muscles
• vertical forces

  • weight
  • reaction force
• Types of frictional force

  • static
  • sliding
• static friction force- force extended on one surface by another when there is no motion between the two surfaces
• sliding friction- two bodies in contact with each other that may have a tendency to slip/slide over each other