# Determine the magnitude of the resultant force

Homework Statement
If $$F_{B} = 5kN$$ and the resultant force acts along the positive u axis, determine the magnitude of the resultant force.

The attempt at a solution

$$F_{Rx} = F_{R}cos 30$$

$$F_{Ry} = F_{R}sin 30$$

$$F_{Rx} = 3 + 5cos\theta$$

$$F_{Ry} = 5sin\theta$$

Therefore, $$\frac{3 + 5cos\theta}{5sin\theta} = \sqrt{3}$$

Is this correct so far? I don't know how to isolate $$\theta$$

Last edited:

diazona
Homework Helper
What variable is the problem asking you to find?

What variable is the problem asking you to find?

It is asking for the resultant force which acts along the u axis.

It is asking for the resultant force which acts along the u axis.
That is right so you don't have to find $$\theta$$

That is right so you don't have to find $$\theta$$

Then how would I go about finding the resultant force? Using a combination of the equations I posted in my attempt?

diazona
Homework Helper
Yep. I asked which variable the question was asking for for a reason; make sure you know which variable you need to find the value of and don't let it disappear when you combine the equations.

Yep. I asked which variable the question was asking for for a reason; make sure you know which variable you need to find the value of and don't let it disappear when you combine the equations.

But I still don't see how I can solve for the resultant force without first solving for theta. Am I missing something?