What is the Tension in the String and the Mass of the Bar?

[Chewy0087]

Homework Statement

The bar is maintained horizontal & in equilibrium by an angled string which passes over a pulley and which carries a mass of 2kg at it's free end.

1) Calculate the Tension T in the String

2) Show that the mass of the bar is approximately 3.5kg

Homework Equations

-

The Attempt at a Solution

Included the picture there, it's a really easy question I guess but i think I'm missing something , or not understanding something very well...

for 1) I presume it's simply 19.6 N , the weight of the mass.

2) I'm a bit stuck here, what does it want you to use? If 19.6 in the tension in the string and you resolve it vertically I get 19.6cos 30 = 16.97 N which obviously doesn't work out to be 3.5kg, I think I'm missing something regarding the pivot, or maybe it's related to work done...

Any help would be great, it's just a stupid problem! :P

Edit: Using that work done thing - I got

(0.8 * 3.5) / cos (30) = 3.23 but still that's far off, so i don't think it can be that

 

[davieddy]

Moments

 

[Chewy0087]

=P thanks