Solving for Unknown Force with Two Given Forces and Constant Velocity

[shell4987]

Homework Statement

While two forces act on it, a particle is to move at the constant velocity = (3.9 m/s) - (-3.6 m/s). One of the forces is 1 = (1.446064618687 N) + (-5.679751753869 N). What is the other force?

Homework Equations

f=ma

The Attempt at a Solution

I don't know an equation to use with velocity in it that would work for this problem. Can someone help me out?

 

[Astronuc]

Since the particle is moving at constant velocity, there is no acceleration, therefore the net force or sum of forces = 0. The components of the other force must be equal in magitude and in the opposite directions.

 

[Doc Al]

The key point is that the velocity is constant. What does that tell you about the particle's acceleration and the net force on it?