Definition: An object at rest stays at rest, and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
Balanced Forces
Characteristics:
Equal in magnitude and opposite in direction
Do not change the speed of a moving object
Do not cause a stationary object to move
Key Concept: Forces have both magnitude and direction
Unbalanced Forces
Characteristics:
Not equal in magnitude
Cause a change in the motion of an object
Net force is the difference between the two forces
The direction of the net force is the direction of the larger force
Impact: The motion of an object will change in the direction of the net force
Real World Examples
Pull Balls: Balanced Forces
Downward force of gravity = Resistance force of the pull table
Strike of the white ball causes unbalanced forces, making red balls move.
Weights: Balanced Forces
Downward force of gravity = Resistance force of the yellow rack
Weight lifter exerts an unbalanced force upward, causing weights to move.
Tennis Balls: Balanced Forces
Equal forces, no motion
When struck by an unbalanced force, they move.
Car and Car Jack: Balanced Forces
Resistance force of the car = Downward force of gravity
Car jack exerts unbalanced force upward, moving the car.
Moving car hitting a stationary car results in unbalanced forces and motion.
Conclusion
Further Information: Playlist available for more details on balanced and unbalanced forces
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