Unbalanced forces are acting on an object when the forces acting on it do not cancel each other out. In the provided scenarios, the situation where unbalanced forces act on the tire is:
Two people stand on the same side of a large tire. One person pushes the tire and the other pulls the tire with equal force.
In this case, the forces exerted by the two people are in opposite directions, but since they are pushing and pulling with the same force, they do not cancel each other, resulting in unbalanced forces acting on the tire.