Distance and Displacement

Motion An object is in motion when its distance from another object is changing. If no change than no motion is perceived

Frame of Reference Frame of Reference is a place or object that you assume is fixed. observations of how objects move in relation to that frame of reference Perception of motion depends on the observer’s frame of reference. Humans usually use the Earth as their frame of reference.

Measuring Distance Distance: The length of a path between 2 points. Distance is measured according to the amount of distance involved Ex: Marble rolls = mm or cm Car travels = m or km

Displacement is a distance with a direction attached to it. Displacement: the direction from the starting point and the length of a straight line from the starting point to the ending point. Displacement is what we use to give people directions to our house. Ex: Walk 5 blocks north from the school; take a right Displacement is a distance with a direction attached to it.

Displacement vs. Distance

Combining Displacements An example of this is a Vector. This is a quantity that has a magnitude and a direction. Magnitude = size length or amount Arrows on a graph are used to represent vectors. The length of an arrow shows the magnitude of a vector

Examples Combining Displacements Vector addition is the combining of vector magnitudes and directions Ex: 5 km 10 km 5 + 10 = 15 km 10 km 3 km 10 – 3 = 7 km