Problem 2 If the magnitude of the resultant force acting on the bracket is to be 450 N directed in the positive u axis, determine the direction angle...

If the magnitude of the resultant force acting on the bracket is to be 450 N directed in the positive u axis,determine the direction angle ϕ of F1, and the magnitude of F3. [Hint: Set up two equations for two unknowns ϕ and F3]