Tweedimensionaal Krachtsysteem

Consider a structural element in a two-dimensional space where a force acts at an angle theta with the x-axis.

Considering that the line of action of the force passes through the origin, its components can be expressed in the Cartesian form. The direction of the force vector is always given by tan inverse of the ratio of its components.

Now, even if the line of action of the force vector does not pass through the origin, its vector components can still be expressed in Cartesian form. The sign convention of these vector components can be chosen depending on their direction.

Here, the force is directed at an angle pi minus theta, measured counterclockwise from the positive y-axis.

Now, consider a structure where the line of action of the force makes an arbitrary angle alpha minus beta to the positive x-axis of the chosen coordinate system. The components of the force can be resolved using a similar analysis.