Determine the design angle theta for connecting member A to

Determine the design angle theta for connecting member A to the plate if the resultant force is to be directed vertically upward. Also, what is the magnitude of the resultant?

Solution

cos(theta) = Fb/Fa

= 400/500

cos(theta) =4/5

theta = 36.9 degree

now the vertical force = Fa sin(theta)

=500 * sin(36.9)

=300.2

= 300 approx

so Option D) is ANSWER