Final answer:
In a tug-of-war where two people pull with equal forces of 400 N and the rope is in static equilibrium, the tension in the rope is 400 N.
Step-by-step explanation:
When two people participate in a tug-of-war and each pulls with a force of 400 N, the tension in the rope would be 400 N, as long as we assume there is no movement and the forces are balanced (nobody is winning or losing the tug-of-war). The tension in the rope is equal to the force applied by each person because the rope is in a state of static equilibrium, where the forces in each direction cancel each other out. The rope transmits the same force applied by each person to its opposite ends, creating tension throughout the rope.