Finding magnitude of the tension of a cord

[schyuler2]

Homework Statement

A 20kg block is held in equilibrium by two massless cords, A, B. A is attached to the wall and B is attached to the ceiling. Find the magnitudes of the tensions of the cords.

Visual: http://i758.photobucket.com/albums/xx228/schuyler2_va/untitled.jpg?t=1260816320

Homework Equations

\Sigma Forces = m*a

Normal force = mg(cos \theta)

The Attempt at a Solution

\Sigma Forces = Tension of A + Tension of B + W + N
Tensions+Weight = ma

N = mg(cos theta)
W = 0
Tension A =?
Tension B=?

^not sure how to find the magnitudes

 

[PhanthomJay]

Homework Statement

A 20kg block is held in equilibrium by two massless cords, A, B. A is attached to the wall and B is attached to the ceiling. Find the magnitudes of the tensions of the cords.

Visual: http://i758.photobucket.com/albums/xx228/schuyler2_va/untitled.jpg?t=1260816320

Homework Equations

\Sigma Forces = m*a

Normal force = mg(cos \theta)

The Attempt at a Solution

\Sigma Forces = Tension of A + Tension of B + W + N
Tensions+Weight = ma

N = mg(cos theta)
W = 0
Tension A =?
Tension B=?

^not sure how to find the magnitudes

There isn't any normal force in this problem, just gravity and tension forces. Why do you say W=0 when it is given that the block has a mass of 20 kG? And since the block is in equilibrium, sum of forces is 0, because a is 0. When you sum forces, look in the x and y directions separately, or else the problem becomes vectorially overwhelming. Note that the upper cord has an x and y component of tension, while the horizontall cord has a horizontal component only.