any action or influence that may accelerate an object

a push or a pull

It exists as a result from an object’s interaction with another object.

It comes/occurs in pair.

It is exerted BY something ON something.

Its SI unit is Newton (N).

At the end of the lesson, the students are expected to:1. state in words and in equation Newton’s

third law of motion;

2. identify action-reaction forces in a real-life situation; and

3. demonstrate teamwork in the activity.

“For every action force there is an equal and opposite reaction force.”

In equation, it can be expressed as:

Aon BBon A FF

Forces occur in pairs.

• Example: For object A and B:

Action force: “ A pushes B”

Reaction force: “B pushes A”

The action and reaction forces occur at exactly the same time!

In Newton’s Third Law, “equal” means:

• Equal in magnitude (strength).–The action and reaction forces have

exactly the same MAGNITUDE.Example:

If Bob pushes the wall with 400 N of force, then the wall pushes Bob with 400 N of force too.

In Newton’s Third Law, “opposite” means:

Example:If Bob’s foot kicks the soccer ball forward, then the soccer ball kicks Bob’s foot backwards.

A. Complete the following statements about Newton’s third law of motion. Underline the correct word from the options given after each statement.

1. The action and reaction forces have exactly the same _______________.(magnitude direction)

2. The action and reaction forces have opposite _____________.(magnitude direction)

3. If a magnet pulls a paper clip up with 2 N of force, then the paper clip pulls the magnet down with ________ force. (similar lesser)

B. Identify the pair of forces in the following pictures.

1.)

2.)

Action force: ____________________

Reaction force:_________________

Action force: ____________________

Reaction force:_________________

In a one-half sheet of paper, answer the following questions.

1. What is work?2. What is energy?3. How are work, energy and power

related?