# Force diagrams, Quick Question

#### circuscircus

1. Homework Statement
http://img61.imageshack.us/img61/4585/8m1cdhx1.gif [Broken]

I understood every except, How do they get the 9 degrees in part c?

2. Homework Equations

3. The Attempt at a Solution

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#### Doc Al

Mentor
Look at the components of the resultant of the three forces: using an inverse tangent you should be able to find the angle it makes with the x axis. (Draw a right triangle.)

#### circuscircus

So then is arctan(30/190) 9 degrees?

(I don't have access to a radian calculator right now), also how do they get the 19N?

#### Doc Al

Mentor
So then is arctan(30/190) 9 degrees?
Yes.
(I don't have access to a radian calculator right now), also how do they get the 19N?
You don't need a radian calculator. (If ever you don't have a calculator handy, Google has one.)

The 19 N makes no sense. But the components are close enough, so you should be able to figure the magnitude properly from that.

#### circuscircus

So the real F is sqrt(130^2+30^2) am I correct?

#### Doc Al

Mentor
So the real F is sqrt(130^2+30^2) am I correct?
Where did the 130 come from?