1. Understand the Forces:

* Applied Force (F_applied): Carlos pushes with 9 Newtons.

* Frictional Force (F_friction): This force opposes the motion and acts in the opposite direction. We don't know its value yet.

* Net Force (F_net): This is the overall force acting on the box. It's the difference between the applied force and the frictional force.

2. Apply Newton's Second Law:

Newton's Second Law of Motion states: F_net = m * a

* F_net: The net force acting on the object.

* m: The mass of the object (3 kg).

* a: The acceleration of the object.

3. Calculate the Net Force:

To find the net force, we need to know the frictional force. Unfortunately, the problem doesn't give us that information. We can only solve for the acceleration if we assume there's no friction or are given the frictional force.

4. Two Scenarios:

* Scenario 1: No Friction

* If there's no friction (F_friction = 0), then F_net = F_applied = 9 Newtons

* a = F_net / m = 9 N / 3 kg = 3 m/s²

* Scenario 2: Friction Present

* If we know the frictional force, we can calculate the net force and then the acceleration using F_net = F_applied - F_friction.

Let me know if you can provide the frictional force, and I can help you calculate the acceleration!