Final answer:
The net force acting on an object at position c can be determined by using vector addition of all forces acting on the object. If, for instance, an object is subject to 30.0 N to the right and 40.0 N upward, the net force would be diagonally upwards to the right. The exact direction of the net force depends on the relative magnitudes and directions of all forces involved.
Step-by-step explanation:
The direction of the net force acting on an object is determined by the vector sum of all the acting forces. When considering the forces acting on an object at position c, one must add the vectors representing each force together to find the resultant force. For example, if you have two forces such as F₁ = 30.0î N in the horizontal direction and F₂ = 40.0ê N in the vertical direction, you would use vector addition to find the net external force (Fₙ₅ₑ).
If position c represents a point where only the forces F₁ and F₂ are acting on an object, then the net force would be a vector with a horizontal component of 30.0 N to the right and a vertical component of 40.0 N upwards. Consequently, the net force would be directed diagonally upwards to the right. To determine the actual direction for a given situation, one should break down the forces into their x-axis and y-axis components, if not already given, and sum them accordingly.
In the context where the net force is the sum of forces like a horizontal push to the right and friction acting to the left, after the push is stopped, the net force will depend on whether the frictional force outweighs the residual force from the initial push. If it does, the net force will be directed opposite to the direction of the initial push; if it does not, the net force remains in the direction of the initial push.