Where and When Section 2-2

Coordinate Systems Coordinate system – defines the location of the zero point and the direction in which the values increase Origin – the point at which both variables have the value zero Position – the separation between the object and the origin You can have an object with a negative position Distance – how far an object is from the origin

Vectors and Scalars Vector – a quantity that has both magnitude and direction Magnitude – size Vectors can be represented by arrows Ex: Velocity and Acceleration Scalar – a quantity that is just a magnitude without any direction Ex: Temperature, time or distance

Adding Vectors Adding vectors is similar to adding scalars or regular numbers Ex: You walk .5 mi. east to school. After school you walked 1 mi. east to a friends house. How far from the origin are you at the end of the trip? 1.5 mi. east Resultant – the vector that represents the sum of the other two vectors

Time Intervals and Displacements Time Interval – the difference between two times Equal to the final time minus the initial time Δt = tf – ti Displacement – change in position Equal to the final position minus the initial position Different than distance Δd = df – di

Vector Subtraction Reverse the subtracted vector and add it to the other This can be done because: A – B = A + (-B) Ex: You drive 5 mi. North to Sheetz. You then drive 2 mi. south to your grandmother’s house. How far are you from the origin? 3 mi. North

Tip to Tail When adding vectors using graphs, place the tip of the second vector to the tail of the first vector. The resultant is then the vector that connects the tip of the first vector to the tail of the second