States that an object at rest stays at rest, and an object in motion stays in motion with the same speed and direction unless acted upon by an unbalanced force.
Balanced Forces
Cause no change in the speed of an object.
Act in opposite directions and have equal strength.
Example: Objects that are not moving will not start moving if acted upon by balanced forces.
Unbalanced Forces
Are not equal and result in a change in motion of an object.
When exerted in opposite directions, the combined force equals the difference between the two forces.
The net force's magnitude and direction affect the resulting motion, and the object moves in the direction of the larger force.
Real-World Examples
Pool Table
Balanced: Red pool balls have balanced forces with gravity and the pool-table’s resistance.
Unbalanced: When the white ball strikes, red balls move in the direction of the force.
Weights and Weightlifting
Balanced: The downward force of gravity is equal to the resistance of the rack.
Unbalanced: A weightlifter exerts an upward force, moving the weights.
Tennis Balls
Balanced: Forces on the tennis balls are equal, so they don't move.
Unbalanced: When struck, the balls move.
Car and Car Jack
Balanced: The car is at rest with balanced forces of gravity and resistance.
Unbalanced: The car jack exerts an upward force, moving the car.
Unbalanced (collision): A moving car strikes a stationary car causing the stationary car to move.
Conclusion
Understanding of unbalanced and balanced forces is key in predicting motion changes.
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