Hunter Hodge

Jacob Johnson

Teachers:

**Unbalanced Forces**

Definition: two or more forces acting on an object that do not cancel, and cause the object to accelerate.

Unbalanced forces are not equal and opposite. Suppose that one of the teams in tug of war pulls harder than the other team. The forces would no longer be equal. One team would be able to pull the other team in the direction of the larger force.

Examples of Unbalanced Forces

1.) When unbalanced forces act on an object at rest, the object will move. The net force on the object is greater than zero. Unbalanced forces produced change in motion (acceleration) and the receivers of the forces move. Unbalanced forces are necessary to cause a non moving object to start moving.

2.) When unbalanced forces act on a moving object, the velocity of the object will change. Remember that a change in velocity means a change in speed, direction, or both speed and direction. For example, consider a soccer game. The soccer ball is already moving when it is passed from one player to another. When the ball reaches the second player, the player exerts and unbalanced force - a kick - on the ball. After the kick, the ball moves in a new direction and with a new speed

Unbalanced forces can change the motion of an object in two ways.

Unlike balanced forces, unbalanced forces always cause a change in motion. They are not equal and opposite.

Suppose tugboat A exerts a force of 2000 Newtons on the barge, and tugboat B exerts a force of 4000 Newtons in the opposite direction. What is the combined force on the barge?

Try it out

What is Unbalanced Force

Pushing a stalled car to a mechanic

Sliding Furniture across the floor

When there is a net force acting on an object, the force is said to be unbalanced.

An unbalanced force can cause an object to

start moving, stop moving, or change direction

. An unbalanced force acting on an object will change the objects motion.

When two unbalanced forces are exerted in opposite directions, their combined force is equal to the difference between the two forces and is exerted in the direction of the larger force. Look at the following examples to help make this more clear.

Think about an arm wrestling match. Imagine that you are competing against a world famous body builder. Chances are that his force will be much greater than yours. Your arms will move in the direction he is pushing with a force that is equal to his force minus your force.

Remember...

Forces in the

SAME

direction Combine together by addition(+)

Forces in the

OPPOSITE

direction combine together by subtraction(-)

Since the forces are opposite you subtract

4000Newtons -2000Newtons

equals 2000 Newtons

Group Work!

1.)

True or False: An unbalanced force does not affect motion.

2.)

True or False:When an unbalanced force is exerted on a resting object, the object accelerates in the direction of the unbalanced force.

3.)

Define Unbalanced Force

4.)

Give 3 examples of unbalanced forces

5.)

why is unbalanced forces different than balanced forces?

6.)

speeding up,slowing down, and changing direction are all due to what?

Answers!

1.)

False

2.)

True

3.)

Two or more forces acting on an object that do not cancel, and cause the object to accelerate.

4.)

Tug-of-War,pushing a stalled car to the mechanic.

5.)

Unlike balanced forces, unbalanced forces always cause a change in motion. They are not equal and opposite.

6.)

Unbalanced Forces

Activity!

Now consider a book sliding from left to right across a tabletop. The force of gravity pulling downward and the force of the table pushing upwards on the book are of equal magnitude and opposite directions. These two forces balance each other. Yet there is no force present to balance the force of friction. As the book moves to the right, friction acts to the left to slow the book down. There is an unbalanced force; and as such, the book changes its state of motion.