Vectors: Position and Displacement

Position() is the separation and direction from a reference point and a reference point is a start position or origin. Let's say a biker, rode from his start point 130 metres east (=m [E]) . You can see how the distance and direction is stated; this is called a Vector quantity. A quantity that only involves size and no direction is called a Scalar quantity.

Displacement is the change in position. The symbol from displacement is . To calculate the total change in displacement you subtract 1 from 2 to get the change in displacement(). Displacement is a vector quantity as well, it is represented as 33m [w] (it has both a measurement and direction).

Sometimes we travel backwards and forwards, but in order to find the change in displacement, we must give the measure(value) a negative or positive value according to the direction. Let's say you moved forward 20m, if you were to write this out in number form only, then it would be +20m. If you travelled backwards, then you would usually make the measured value a negative integer. Imagine you walked backwards 3 meters that would make its value -3. What would be the total displacement assuming you started +20m and ended -3m's.

(+20) - (-3) = 23

 Sample You're running from a pact of killer bees, you run (45meters east from camp (0m). What is your total change in displacement? Let east be positive and west be negative. = d2 - d1 = 45 - 0 = 45 Therefore the total change in displacement is 45[east]

Drawing Vectors

A vector is a line segment that represents the size and direction of a vector.
The following rules must be taken into affect when drawing vectors

- state the direction - usually using N,E,S, or W as reference
- Draw the line to the state scale or write the size of the vector next to the line.
- The direction of the line represents the direction of the vector , and the length of the line represents the size of the vector.

Continue to the next lesson: Adding Vectors 1