In which situation are unbalanced forces acting on an object?
A. Two people stand on opposite sides of a large tire. Both people pull the tire with equal force.
B. Two people stand on opposite sides of a large tire. Both people push the tire with equal force. C. Two people stand on the same side of a large tire. Both people pull the tire with equal force.
D. 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.
The Correct Answer and Explanation is:
The correct answer is:
D. 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.
Explanation:
Unbalanced forces occur when the net force acting on an object is not zero, causing the object to accelerate, change direction, or deform. In the context of Newton’s First Law of Motion, an object will only change its state of motion if unbalanced forces act upon it. In contrast, balanced forces result in a net force of zero, meaning there is no acceleration, and the object either remains stationary or moves at a constant velocity.
In option D, two people are on the same side of a large tire, and each applies a force in a different manner: one person pushes while the other pulls with equal force. Even though the magnitudes of these forces are the same, their directions are different. The pushing force exerts pressure toward the object, while the pulling force exerts tension away from the object. Since the forces are not aligned in the same direction, they do not cancel each other out completely, resulting in an unbalanced force. This unbalance will likely cause the tire to tilt, rotate, or move, depending on the strength and angle of each applied force.
For comparison, in options A and B, two people exert equal force in opposite directions, which results in balanced forces. Since the magnitudes and directions cancel each other out, there is no net force acting on the tire, so it remains stationary. In option C, both individuals are on the same side and apply equal force in the same direction, combining to create a balanced force that moves the tire in a steady motion without acceleration or change in direction.
Thus, only option D meets the criteria for unbalanced forces due to the opposing nature of the push and pull applied by the two people.