Balanced and Unbalanced Forces

Balanced and Unbalanced Forces

What effects do balanced and unbalanced forces have on the motion of objects?

Forces Review​

​A Force causes an object’s motion to change through pushes or pulls.

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Friction is a type of force that stops or slows down an object's motion​ and is produced between two surfaces or two objects that are touching one another.

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​Magnetism, static electricity, and gravity are all types of forces that move objects without touching them.

​Balanced and Unbalanced Forces

More than one force can act on an object at once.

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If one of those forces is stronger than the other, it is callen an unbalanced force, and the object will move.

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​If both forces have the same strength, it is called a balanced force. Balanced forces make objects stand still.

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​Example of Balanced Forces

Imagine you are playing tug-of-war with your friends. Your team starts by pulling really hard, with all its strength. But the other team is also pulling with an equal amount of force and in the opposite direction. The flag in the middle of the rope does not move. The flag does not move because the force your team is pulling with is equal to the force applied by the other team but in the opposite direction. The forces are in opposite directions. The forces on the rope are balanced. When the forces are balanced, the flag in the center of the rope will not move. To win the game, one team must apply more force than the other.​

​​Example of Unbalanced Forces

By applying an unbalanced force, you can change the motion of an object. Unbalanced forces can make an object at rest start moving, make a moving object stop, or change the direction and speed of the object. Think back to the game of tug-of-war. At the start of the game, both teams pulled equally hard on opposite ends of the rope. The two teams pulled with balanced forces. The flag in the middle of the rope did not move.​

​More Examples of Balanced and Unbalanced Forces

​Examples of balanced forces

include:

• ​doing a handstand without falling

• ​an object floating in water

• ​a person standing or sitting still

• ​framed pictures hanging on a wall

• ​a jacket hanging on a coat hook

• ​a running car staying in place because the brakes are applied

​​Examples of unbalanced forces include:

• ​an object sinking in water

• ​doing a cartwheel

• ​riding a skateboard

• ​a fruit dropping from a tree

• ​an object getting knocked over.

• ​a football sailing toward the goalpost after it is kicked

Multiple Choice

What is a balanced force?

• when two forces with unequal strengths are acting on an object.

• when two forces with equal strengths are acting on an object.

• when two forces with little strength are acting on an object.

• when two forces with a lot of strength are acting on an object.

Multiple Choice

What is an unbalanced force?

• when two forces with equal strengths are acting on an object.

• when two forces are acting on an object.

• when two forces with unequal strengths are acting on an object.

• when only one force is acting on an object.

Multiple Choice

What example below is an example of a balanced force?

• A ball being caught in mid-air.

• A bicycle that is parked and not moving.

• A ball being thrown to another person.

• A bicycle that is moving down a hill.

Multiple Choice

What example below is an example of an unbalanced force?

• A basketball that is not moving.

• A rope being pulled with the same strength in both directions.

• A football that is resting on a kickoff tee.

• A soccer player kicking a soccer ball across the field.