Statics Question: Finding resultant force and orientation

AI Thread Summary
The discussion focuses on calculating the resultant force and its direction based on given forces F1 and F2. The magnitude of the resultant force was correctly determined to be 402 lb. However, there is confusion regarding the calculation of the direction, with an initial angle of 71.6 degrees being misapplied. The correct approach involves finding the components of both forces and then determining the angle relative to the positive x-axis. Clarification is sought on whether to subtract from 360 degrees or adjust the angle differently to express it counterclockwise.
Chandasouk
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Determine the magnitude of the resultant force FR. Assume that F1 = 230 and F2 = 395
Express your answer to three significant figures and include the appropriate units.

Determine the direction of the resultant force FR , measured counterclockwise from the positive x axis.


I got the magnitude as 402lb which is correct, but I am having trouble finding the direction of the force.

I have the following work below

http://img5.imageshack.us/img5/1954/resultantforce.png

So I get \phi=71.6 degrees

Now the first quadrant has an angle from F1 to the x-axis that measures at 60 degrees. What I did was 71.6-60 degrees = 11.6 degrees and said that was the angle of the resultant force, but this answer is wrong.

Can anyone explain how to find the angle? Should I be subtracting 360 from 11.6 degrees instead since it wants the position counterclockwise?
 
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Why don't you find the components of F1 and F2 and add them to determine the resultant?
 
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