Sign of Position
We often define a coordinate system when expressing position. If the object is constrained to move in one dimension, we can use a single axis as our coordinate system. If the object moves in two dimensions, we can use the horizontal and vertical axes of the Cartesian Coordinate System.
When expressing position on a horizontal axis, we often consider those locations to the right of the origin to be positive and the locations to the left of the origin to be negative. This is just a convention, not a rule; you can define positive as any direction you want!
When expressing position on a vertical axis, we often consider those locations above the origin to be positive and the locations below the origin to be negative. This is just a convention, not a rule; you can define positive as any direction you want! 

Click the image at the left to download "The Moving Man" simulation from the PhET website. After you are finished downloading the simulation, follow the directions given below. 
If you need help, use the office hours chat below.
Let's See What You Know About Position.
Click HERE to see what you know about the sign of position. A document will open. After the page opens, scroll down until you see "Physics 221 Worksheet: Signs of Kinematic Quantities." Then try to answer the questions. Solutions are at the bottom of the page.