How to Determine the Angle for Optimal Force Direction in Engineering?

[fball558]

Engineering question about angle??

Homework Statement

Determine the angle (theta) for connecting member 1 to the plate soo that the resultant force of F1 and F2 is directed horizontally to the right. Also, what is the magnitude of the resultant force?
i drew a sketch diagram up in paint to help me but it did not. here is what i made.

Homework Equations

i know you will have to use some trig like cos and sin
also maybe law of cos

The Attempt at a Solution

i did the sketch also i tried braking down the both the F1 and the F2 into x and y components but got stuck on the x and y components for the F1 because i get for
x= 8 cos (90 - theta)
any help would be great.
thanks

 

[Doc Al]

i did the sketch also i tried braking down the both the F1 and the F2 into x and y components but got stuck on the x and y components for the F1 because i get for
x= 8 cos (90 - theta)

So far, so good. Keep going. (Note that you can also express that x-component using sinθ.)

 

[fball558]

sin θ = Fr/8 where Fr is the resultant force. but that is 2 unknowns and i don't know what to do from there. i don't have the textbook for this class, the book store ran out or i would just look in there for examples.

 

[Doc Al]

sin θ = Fr/8 where Fr is the resultant force.

One step at a time. You haven't gotten to the resultant force yet. You're still finding the x-component of F1: F1_x = 8 sinθ. Now find F1_y, F2_x, and F2_y.