Finding Tensions (3 strings and 1 mass)

[Prima]

Homework Statement

In the picture, what are the tensions in strings 1, 2, and 3?

http://www.flickr.com/photos/90172232@N04/8194075362/

Homework Equations

The Attempt at a Solution

I know string 3 is obviously 200N. I forget how to solve for the other strings. Do I add vectors here? string 1 = ?*sin(70) perhaps. Can somebody just point me in the right direction with this?

 

[haruspex]

At the junction, you have some forces acting. There is no acceleration. Draw a free-body diagram for the junction and write out equations representing the lack of acceleration.

 

[tiny-tim]

Welcome to PF!

Hi Prima! Welcome to PF!

Start by giving things names …

call the tensions T₁ and T₂.​

Then write the equations for components in the x and y directions.

(alternatively, draw a vector triangle)