Tension finding problem, need help.

[Godad]

I was wondering if someone could help me out with this problem. Here is the question...

The 10.2 kg block in the picture is held in place by the massless rope passing over two massless, frictionless pulleys. Find the tensions T1 to T5 and the magnitude of force F.

Here is the picture...


http://www.blinkysrus.com/iidx/tension.gif


I somewhat understand how to find T1 through T2, but I'm having a hard time with finding F.

[Skomatth]

Could you tell us what you got for the tensions? What effect is F having on the system (its keeping the block up) so what does that say about the relation btw F and the tension in the rope.