# Newton's Second Law Problem

1. Oct 14, 2007

### Seraph404

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

While two forces act on it, a particle is to move at the constant velocity v = (3 m/s)i - (4 m/s)j. One of the forces is F1 = (2N)i + (-6N)j. What is the other force?

2. Relevant equations

Fnet = ma

3. The attempt at a solution

Well, I'm really just wanting a hint. I know that the acceleration is zero because the velocity is constant. So how do I use velocity to find the second force? Surely I'm missing something fundamental here. Once again, just a hint would be nice.

2. Oct 14, 2007

### PhanthomJay

You pretty much gave yourself a hint when you said that there is no net force. Since one of the two forces are given, what's the other one?

3. Oct 14, 2007

### Seraph404

(-2N)i + (6N)j ?

4. Oct 14, 2007

### PhanthomJay

Correct! (the answer would be the same regardless of the value of the constant velocity).

5. Oct 14, 2007

### Seraph404

Oh okay! Thanks!