The system shown is commonly used for supporting a rural mailbox. It has the feature tha...

The system shown is commonly used for supporting a rural mailbox. It has the feature that the mailbox can swing about line a if it is subjected to a z direction force, preventing possible damage to the mailbox and supporting post. Line a lies in the xy plane. The 150N force acts in the -y direction, the 200N force has the direction specified below, and the lines of action of each of these pass through point C. Determine the moment of the 150N and 200N forces about line a.

The 200N force has the direction angles