# Homework Help: Physics problem: tension.

1. Oct 12, 2009

### Fanekaz

1. The problem statement, all variables and given/known data
There are two bodies, A and B, body A as 4,0 kg and B as 8,0 kg, the bodies are in a horizontal surface, with no friction. Both bodies are connected by a non-extensible string with unknown mass, which doesn't matter to the case.
The bodies are moving under de action of a force which has 18,0N of intensity.
So I have to discover the intensity of the tension, which I happen to know the answer that is 12N, I just can't get there.

2. Relevant equations
Resulting force=Weight+wheight+Fn+Fn+t+t+Friction+F
I think so....

3. The attempt at a solution
I really don't know how to solve this, I tried several times and searched for some formulas but i cant get 12N.............
Sorry about my poor english i'm portuguese.
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Oct 12, 2009

### kuruman

The two masses move together with the same acceleration under the influence of a single force of 18 N. Can you find the common acceleration of the masses? That will be a good first step.

3. Oct 12, 2009

### Fanekaz

thanks i will try that