# Homework Help: Find tension with two cables at different angles

1. Oct 6, 2011

### gmuck

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

A weight of 5000 N is suspended by two cables. The object is at rest. The first cable is horizontal and the second makes an angle of 143 ° with the first cable. Find the tension of the first cable.

2. Relevant equations
Erm...I know it's something with sin or cosin.

3. The attempt at a solution
My teacher hasn't given us any equations that have to do with tension, so I am completely and utterly lost. Any help would be greatly appreciated!
It's multiple choice and the possible answers are
4000 N
6640 N
8310 N
3340 N

2. Oct 7, 2011

### U.Renko

if the object is at rest, then accelersation is zero.
if accelaration is zero, then the net force is zero.

3. Oct 7, 2011

### Cipherflak

The tension is just the force exerted by the cables.

Have you made a drawing and applied the three forces working?

4. Oct 7, 2011

### MrNerd

Indeed, there is some sin or cos involved. As mentioned above, the acceleration is zero. What does this imply about the vertical part of the tension?

5. Oct 7, 2011

### Cipherflak

if you break the problem into a horizontal and a vertical part, the sum of forces should be 0 in each of these.

in the horisontal, the force on cable 1 must be equal to the HORIZONTAL PART of the force of cable 2.

In the vertical the VERTICAL PART of cable 2 must balance gravity.

Agree?

Last edited: Oct 7, 2011