# Tension in a cord with Vectors, getting started

1. Oct 11, 2007

### lim

1. The problem statement, all variables and given/known data

Find the tension in cord 2, shown in figure below. Neglect the mass of the cords, and assume that the angle q(theta) is 29.7 ° and the mass m is 190 kg.

Find the tension in cord 1.

2. Relevant equations

T2CosQ2 - T1cosQ1= 0
T1SinQ1 + T2SinQ2 - m(g)=0

3. The attempt at a solution

Isn't there a AIA angle property that would make the angle opposite and adjacent to theta( 29.7) equal to it, and that would be Q2(the angle for cord 2).

So
cord 2 = T2Cos(29.7) - T1cosQ1= 0, but how do I find the angle for cord 1? I can't assume that it's 90 degrees.

Helpp

2. Oct 11, 2007

### Staff: Mentor

It looks like cord 1 is horizontal. That's what I would assume.

3. Oct 11, 2007

### lim

so for cord 2 I did T2CosQ2 - T1cosQ1= 0
T2 Cos(29.7) - T1 Cos(90) = 0
T2 .868 -0= 0
T2 = 0.868?

4. Oct 11, 2007

### Staff: Mentor

No. Cord 1 is horizontal, so its angle with the x-axis is 0, not 90.

5. Oct 11, 2007

### lim

T2 Cos(29.7) - T1 Cos(0) = 0
T2 (.868) - T1 (1)= 0
T2 - 0.132= 0
T2 = .132
What else did I miss? My answer isn't right.

6. Oct 11, 2007

### Staff: Mentor

So far, so good.
These steps are mathematically incorrect. The proper next step is:
T2 (.868) = T1

You need to combine this with the equation for vertical forces. You'll get two equations and two unknowns.