Internal stress without external motion – effect of applied equilibrating forces\nIf a given force (or system of forces) acting on a body ______ the position of the body, yet keeps it in overall equilibrium, its effect is to produce internal stress in the body.

Introduction / Context:
Stress can exist in a body even when there is no external motion. Self-equilibrating or balanced external loads may leave the body at rest while inducing internal forces to maintain equilibrium.

Given Data / Assumptions:

• External forces act but net force and net moment are zero (static equilibrium).
• No change in the macroscopic position or orientation of the body.
• Continuum mechanics assumptions apply (internal force transmission through sections).

Concept / Approach:
Equilibrium of the whole body does not imply zero internal forces. Internal stress arises to balance the applied loads over internal cross-sections so that every part is in equilibrium.

Step-by-Step Solution:

Verification / Alternative check:
Cut-free-body approach: section the body and draw free-body diagrams of each part; internal forces and moments appear to balance external loads, proving the presence of stress fields.

Why Other Options Are Wrong:

• ‘‘change’’ implies motion; the statement emphasizes stress without overall motion.
• Options about rotation or acceleration contradict static equilibrium condition.

Common Pitfalls:
Assuming ‘‘no motion’’ means ‘‘no stress’’—internal forces can be substantial while the body remains at rest.

Final Answer:
does not change