statics and the cross product

[Shay10825]

In the problem:
A horizontal boom supporting the sign is of uniform construction and weighs 50 N. If the sign weighs 150 N, the tension in the supporting cable is?

Could I use the cross product and if so how? The answer is 350 N.

[James R]

Do you have a diagram? Is the cable at an angle, or is it vertical? Where's this sign you mention?

[Shay10825]

http://img121.exs.cx/img121/4286/2882.jpg

[cepheid]

Hmmm....is that all the info? Do we have some lengths, or the angle of the cable from the horizontal?

[James R]

The tension in the cable definitely depends on the angle it makes with the horizontal, so we need to know that to solve the problem.