#### Transcript Vector, Scalar and Position Measurement

Vector, Scalar and Position Measurement By: Brandon & Georgie What’s Discussed • Vector Measurement • Scalar Measurement • Position Measurement Vector Measurement • Vector Measurement is defined as a measurement that has both size and direction • Displacement is a vector quantity due to the fact it has size and direction. • Displacement is expressed how far the body or has moved vertically, and laterally. • Force, weight, pressure, specific weight, and torque are kinetic vector quantities. • Examples • trip to the store; (2 blocks, West) • force of gravity; (170 pounds, Down) • velocity; (35 mph, North) Scalar Measurement • Scalar measurement is simply defined as a measurement that only has size • Distance is a scalar quantity and has no direction, meaning it doesn’t matter what direction the object or body moves, only how far it goes. • Mass, volume length and speed are example of scalar quantities • Examples • temperature; (68 degrees, no direction) • cost; ($37.50, no direction) • speed; (35 mph, no direction) Difference Between Vector & Scalar • The difference between these two are important in biomechanics because it affects how measurements are combined. • They can be combined by Adding, Subtracting, Multiplying or Dividing • If the direction of two vectors is the same then there sizes may be combined together. You also need to take into consideration if their in different directions. • Scalar can just be Added, Subtracted, Multiplied or Divided • Vector gives more information Examples in Sports • Throwing a medicine ball the horizontal and vertical components of velocity of the medicine ball indicates the angle of release of the medicine ball is 35° and the velocity at release as 12 metres/second. What is position? • The position of an object or the body is usually given by coordinates. • Linear coordinates are a linear measurement (e.g. metres) from an origin. • They are given in two dimensions (horizontal and vertical) or three dimensions (horizontal, vertical and lateral) • Two dimensional coordinates are often named x and y • Three dimensional coordinates are often named x, y and z • There are two systems for giving three-dimensional coordinates • In the first x is horizontal, y is vertical and z is lateral • In the second x is horizontal, y is lateral and z is vertical • The position of an object is sometimes given as the symbol r Key Concepts • The position of an object or the body is usually given by coordinates. • They are given in two dimensions (horizontal and vertical) or three dimensions (horizontal, vertical and lateral) • The position of an object is sometimes given as the symbol r Examples in sport • Running is an example of where position is used because of looking at the centre of gravity where they give figures in the difference of the position of the centre of gravity when standing and when running. • Golf if also a sport where position is used. Because of the position of how the golfers stand when they do their swing. Videos • Biomechanics of running http://www.youtube.com/watch?v=MqjnbelS3WU • Biomechanics of golf http://www.youtube.com/watch?v=CbJoOWEmdqI