How to Find the Resultant Force of Three Forces Acting on a Point?

[Phantom5800]

I'm sorry that this is probably a repeat topic, but I am having a hard time using other threads as examples. This is probably really easy, I just can't seem to figure it out the way our teacher taught it. I'll try and make this short and simple.

Homework Statement

There are three forces acting on a single point. One is 15 N north; the second is 15 N west; and the final is 15 N at 30 degrees east of north. Determine the magnitude and direction of the resultant force.

Homework Equations

Basic trig (sin, cos, tan), a^2 + b^2 = c^2. This is all we have been taught in this class and are expected (and should be able to) solve with just this.

The Attempt at a Solution

        10 N north
            |  /
            | /   15 N 30 degrees east of north
<-----------|/     
   15 N west

From there I am unsure of what I could do to easily solve it (also a little unsure of what I am even solving for).

 

[Doc Al]

One easy way to add vectors is to find their components (x & y = East-West & North-South) and add them. Then you can find the magnitude and direction of the resultant from its components.

 

[pertunia]

Could you please help me with theory of vectors at equilibrium?

 

[Doc Al]

Could you please help me with theory of vectors at equilibrium?

If an object is in equilibrium, the forces acting on it (which are vectors) must add to zero. Is that what you mean?

 

[24hourtutor]

For the original poster: any question like this, even one with 2034 forces acting on a point, can easily be solved by breaking each vector into x and y components and then adding up to find the resultant. Some people find a chart helpful.

V| x | y
1| 0 | 10
2|-15| 0
3| ?x| ?y

The total in the x direction would be -15 + ?, and the total in the y would be 10 + ?y.

To find ?x and ?y will require some trig.

 

[Doc Al]

For the original poster:

Realize that this thread is about 2 1/2 years old.