To identify the situations with an unbalanced force, we can refer to Newton's First Law of Motion, which states that an object will remain at rest or in uniform motion unless acted upon by an unbalanced force.
Let's analyze each situation:
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A baseball speeds up as it falls through the air.
- This situation has an unbalanced force acting on the baseball (gravity is pulling it down).
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A soccer ball is at rest on the ground.
- This situation does not involve an unbalanced force; the forces are balanced (gravity and normal force are equal).
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An ice skater glides in a straight line at a constant speed.
- This situation also does not involve an unbalanced force; the ice skater moves with balanced forces (assuming no friction or other forces acting on them).
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A bumper car hit by another car moves off at an angle.
- This situation has an unbalanced force (the collision results in a change in motion).
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A balloon flies across the room when the air is released.
- This situation has an unbalanced force (the propulsion of air out of the balloon creates a reaction force that propels the balloon forward).
Based on the analysis, the situations with unbalanced forces are:
- A baseball speeds up as it falls through the air.
- A bumper car hit by another car moves off at an angle.
- A balloon flies across the room when the air is released.