Force is a push or pull that can be measured in Newtons. It is exerted by one object on another and can cause motion. Net force is calculated by adding forces in the same direction and subtracting forces in opposite directions. A net force of zero results in no motion, while a non-zero net force causes unbalanced motion. Force is key to understanding why objects move or are at rest.

1. FORCE

2. What is Force?
• A push or pull
• Force has a size & direction
• All motion is created by a force
• All forces are exerted by one object on
another
**Motion does not have to occur

3. How is Force Measured?
• Measured in Newtons (N)
• The more Newtons, the greater
the force
• One tool to measure the force of
gravity is the spring scale

4. Examples of Force
• Fingers open a book
• Push buttons on a keyboard
• Gravity holds up a chair
• 2 magnets coming together
• The force that results from combining forces
Visible
Forces
Invisible
Forces

5. How to Measure Net Force
SAME
DIRECTION =
ADD
TOGETHER
20N + 25N = 45N
This is the NET FORCE
UNBALANCED
FORCE because it
produces MOTION
Person # 1
Pushing with
20N Force
Person # 2
Pushing with
25N Force

6. How to Measure Net Force
OPPOSITE
DIRECTIONS =
SUBTRACT
25N - 10N = 15N
This is the NET FORCE
UNBALANCED
FORCE because it
produces MOTION
Team # 1
Pulling with
25N Force
Team # 2
Pulling with
10N Force

7. How to Measure Net Force
OPPOSITE
DIRECTIONS =
SUBTRACT
37N - 37N = 0N
This is the NET FORCE
Wrestler # 1
Pushing with
37N Force
Wrestler # 2
Pushing with
37N Force
BALANCED FORCE
because there is NO
MOTION