Balanced and Unbalanced Forces

Balanced and Unbalanced Forces

A Force

A force is a push or a pull that causes a change in an objects motion. Forces are measured in units called Newtons.

Forces work in pairs

There are always two or more forces that affect an objects motion. The size of the forces determines the motion an object will have.

Balanced Forces

When two forces acting on an object are equal and in opposite directions then the forces are balanced and the object will not move. The forces "cancel" each other out.

Unbalanced Forces

When two forces acting on an object are in opposite directions but are not equal then the forces are unbalanced and the object will move. The forces don't "cancel" each other out so there is movement.

Motion of an object

When forces are unbalanced they cause a change in an objects motion. Unbalanced forces can cause objects to start or stop moving, speed up or slow down, or change directions.

Multiple Choice

1. What affect do forces have on an object?

• They can change the motion of an object

• They can make objects bigger

• They can make objects change from one form into another

• They can make objects smaller.

Multiple Choice

2. What type of force causes objects to not move?

• Unbalanced forces

• Balanced forces

Multiple Choice

3. What type of force causes objects to move?

• Balanced forces

• Unbalanced forces

Multiple Choice

4. When the forces acting upon an object are balanced then the object

• will not move

• will move

Multiple Choice

5.When the forces acting upon an object are unbalanced then the object

• will not move

• They can make objects bigger will move

Forces in action

The motion of a baseball that gets hit by a batter changes because of forces.

How forces affect the motion of a baseball

When a batter hits a ball the ball rises into the air and at point A it starts to SLOW DOWN because of the force of gravity.

How forces affect the motion of a baseball

At point C gravity pulls the ball towards the center of the Earth and it SPEEDS UP.