Moving Reference Point

Lesson 4: Position and Motion

How do we discuss location and motion?

​Position

When discussing position, we have to use reference points. A reference point is the starting point you choose to describe a location, or position, of an object.

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​If we describe the distance and direction from the reference point, we then have a position.

​Use Reference Points

​Moving in the Reference Direction

​If you move in the same direction as the reference direction, then you are moving in the positive direction.

​If you move in the opposite direction as the reference direction, then you are moving in the negative direction.

​Position in 2D

Motion in 2 dimensions is typically how we experience the world (3D if flying or jumping). So, if we want to reference position in two ​dimensions, we have to think of both up/down, and left/right.

​Displacement

Displacement is the distance between the starting point and ending point of a body that was in motion.

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​In the diagram to the right, the green line represents the displacement and the blue line represents the distance traveled by the object.

Multiple Choice

The distance between the starting point and ending point is called _________________.

• displacement

• distance

• length

• speed

Multiple Choice

If you designate the east as the reference direction and then move west, did you move in the positive or negative direction?

• positive

• negative

Multiple Choice

If I tell you to meet me in front of my classroom, what is the reference point?

• my classroom

• the school

• me

• you