Unbalanced forces are present when the net force acting on an object is not zero, meaning that the forces acting on it do not cancel each other out.
In the provided options:
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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. (Unbalanced forces: one push and one pull in opposite directions)
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Two people stand on the same side of a large tire. Both people pull the tire with equal force. (Balanced forces: both are pulling in the same direction with equal force)
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Two people stand on opposite sides of a large tire. Both people pull the tire with equal force. (Balanced forces: equal pulling in opposite directions cancel each other out)
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Two people stand on opposite sides of a large tire. Both people push the tire with equal force. (Balanced forces: equal pushing in opposite directions cancel each other out)
The situation that involves unbalanced forces is the first option, where one person pushes and the other pulls the tire with equal force, resulting in a net force in the direction of the push.