To determine which change in force would stop the box from moving, we need to analyze the existing forces acting on it.
If we assume that the box is currently experiencing a net force of 14 N to the left and 8 N to the right, the net force on the box would be:
\[ \text{Net Force} = 14, \text{N (left)} - 8, \text{N (right)} = 6, \text{N (to the left)} \]
To stop the box from moving, we would need to apply enough force in the opposite direction (to the right) to counteract the net force of 6 N to the left.
The correct choice is:
• adding 6 N of force pulling to the right
Adding 6 N to the right would cancel out the net force and bring the box to a stop.