The Component Addition Concept Builder is quite simple to use. You will be presented with a diagram of several letter-labeled vectors on a background grid and a vector addition equation. A scale is also provided that equates the length of the side of a square on the grid to a distance in kilometers (km). Your goal is to determine the magnitude and direction of the resultant or sum of the given vectors. Depending on the difficulty level, you will have to add two, three, or four vectors to add.

To facilitate this, a table is provided for the recording of the x- and y-components of the vectors given in the equation. Use the diagram and the scale to determine these components. There is also a row for recording the sum of these components - also knowns as the components of the resultant. Once you have filled in the table, you can tap on the **Check Table** button. The values that you have recorded in the table will be evaluated and feedback will be given. If any cells are inaccurate or incomplete, then they will be marked by red dots. The red dots will appear to the right or to the left of the table columns next to any incorrect or incomplete answer. You will have opportunities to make corrections.

Once all the table values are correct, you will have to identify the approximate direction of the resultant by tapping on one of eight diagrams. Decide which quadrant the resultant points (e.g., into the southwest or third quadrant) and whether the x- or the y-component is greater. Tap on the diagram consistent with this decision; use the **Check Diagram** button to check the accuracy of your choice. You will be notified of the accuracy of your choice and given ample opportunities to get it correct.

The last part of the problem involves determining the magnitude and direction of the resultant. This involves the use of the Pythagorean theorem and a tirgonometric function. You wll have to report the direction as a counter-clockwise angle of rotation from due East. Once you have filled in the two fields, tap on the **Check Answers** button. Feedback will be immediate and specific. You will be able to correct your answers if wrong.

Once you have completed the vector addition problem, your **Progress Report** will be updated. Your goal is to earn "Stars" and to complete one or more levels of difficulty. Stars are earned when you solve the problem correctly. Once you correctly answer all three questions at a particular difficulty level, you will earn the Medal for that level.

You will notice that there is a **Help Me** button underneath the Progress Report. You should learn to use this feature of the program. It's how you can turn an exercise in answering questions into an exercise in learning. Tapping on the **Help Me** button will open a page with help that is specific to each question. Of course, the Help pages are only helpful if you read them. So take the time to read them. Each Help page contains four sections: a discussion of the **The Basic Concepts**, a display of the **Question **your are facing (or a similar question with different numbers), a section titled "**How to Think About This Situation**", and a set of links to resources in our Tutorial section. You should pay attention to the section titled **How to Think About This Situation**. You will find what you need to know in the three or four paragraphs of this section. You will also become a better Physics student for doing that. That is, after all, the goal of such an activity as **Component Addition**.

Thanks for being patient with the Directions. Happy learning!