Stress is INTERNAL force per unit area, while traction is EXTERNAL for…

Question

Stress is INTERNAL force per unit area, while traction is EXTERNAL force per unit area. Why is traction described as a BOUND vector?

Accepted Answer

C. {'text': 'Because it cannot slide along its line of action — the surface it acts on must be specified', 'label': 'B'}

A bound vector requires its point of application AND the surface (orientation) to be meaningful. The same force F on a different surface S gives a different traction. Free vectors (like translation) can slide; bound ones cannot.

Answer

{'text': 'Because it points downward', 'label': 'C'}

Answer

{'text': 'Because it equals stress', 'label': 'D'}

Answer

{'text': 'Because it has a fixed magnitude', 'label': 'A'}