[P6 Science]: Forces (Part 1)

A force is a push or a pull acting on an object. Forces can make objects move, stop, speed up, slow down, change direction, or change shape.

A push can start motion, speed it up, or change its direction.

Simple examples:

Force action	Everyday example	What happens
Push	Pushing a door open	The door moves away
Pull	Pulling a drawer open	The drawer moves toward you
Twist	Turning a bottle cap	The cap changes position
Stretch	Pulling a rubber band	The rubber band changes shape
Squeeze	Pressing a sponge	The sponge becomes smaller

Forces can be grouped into two main types.

Contact forces need objects to touch. Examples include pushing, pulling, friction, tension, and elastic spring force.

Non-contact forces act without touching. Examples include gravitational force and magnetic force.

Balanced and unbalanced forces explain motion

Forces often act in pairs or groups. To understand what happens to an object, compare the forces acting on it.

When forces are balanced, they are equal in size and act in opposite directions. The object stays still or continues moving at the same speed in the same direction.

For example, a book resting on a table has two main forces acting on it:

• Gravity pulls the book downward.

• The table pushes the book upward.

  
  

The book does not move because the forces are balanced.

When forces are unbalanced, one force is greater than the other. The object’s motion changes.

An unbalanced force can make an object:

• start moving

• stop moving

• speed up

• slow down

• change direction

  
  

Think of kicking a soccer ball. Before it is kicked, the ball is still. The foot applies a force to the ball. The forces are no longer balanced, so the ball starts moving.

A moving ball does not keep rolling forever because friction and air resistance act against its motion. These forces slow it down.

A common mistake: “There is no force because the object is not moving.” A still object can have forces acting on it. The key is whether the forces are balanced.