Vectors

    You may have read that Ben Franklin first became interested in the Gulf Stream because the mail was taking two weeks longer to get from England to the Colonies then from the Colonies to England. The mail was carried on sailing ships in those days and thus if the ships were to sail against the flow of the Gulf Stream it would slow them down (see image below). A good way to think about this is to picture trying to row a boat UP stream against the flow of the water. The speed of the boat would be slowed down because of the rushing water.

Special thanks to Erin Kelly and the students at the Children's Institute for this image
     
    To describe what you see above we use vectors.  Vectors are a way to express both quantity and magnitude.  So, the ship seen above will not only be traveling 5mph, but 5mph in a certain direction.  A vector is always drawn as an arrow.  The direction of the arrow indicates direction and the length of the arrow indicates magnitude.
    The diagram above shows an example of a ship traveling parallel to the Gulf Stream.  What happens if a ship is traveling perpendicular to the Gulf Stream?  In this case, you can't simply add and subtract.  You infact must take into account angles.  This is where the Pythagorean Theorem and trigonometry becomes important.  To learn more about vectors and vector addition use the following links.
Vectors and Direction
Vector Addition
Vector Calculator

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