Newton's 3rd Law

Newton's 3rd Law

Sir Isaac Newton, not Fig Newton

Learning Objective:

• We will investigate and describe applications of the law of action-reaction (Newton’s 3rd Law of Motion).

Sir Isaac Newton

Sir Isaac Newton

Sir Isaac Newton PRS (25 December 1642 – 20 March 1726/27 ) was an English mathematician, physicist, 

astronomer, theologian, and author (described in his own day as a "natural philosopher") who is widely recognized as one of the most influential scientists of all time and as a key figure in the scientific revolution.

Multiple Choice

Trivia Time: Which monarch knighted Isaac Newton in 1705?

• Queen Mary II

• Queen Anne

• King George I

Fig Newton

Delicious Snacc...

Poll

Do you like Fig Newtons?

• Yes.

• No.

Newton's 3rd Law

For every action, there is an equal and opposite reaction. The statement means that in every interaction, there is a pair of forces acting on the two interacting objects. The size of the forces on the first object equals the size of the force on the second object.

Let's break it down...

• The Law of Action-Reaction.

• For every action there is an equal and opposite reaction.

• Forces come in pairs when acting on two interacting objects.

• The size of the force on one object is equal to the size of the force on a second object.

Multiple Choice

What is another name for Newton's 3rd Law?

• The Law of Opposites Attract.

• Fig Newtons.

• The Law of Action-Reaction.

Multiple Choice

For every action there is an equal and opposite reaction.

• True.

• False.

Multiple Choice

Do forces come in pairs when acting on two interacting objects?

• Yes.

• No.

Multiple Choice

The size of the force on one object is equal to the size of the force on a second object.

• True.

• False.

Example

A swimmer pushes back on the water and moves forward.

Multiple Choice

Which is the Action Force in this scenario: "A swimmer pushes back on the water and moves forward."

• A swimmer pushes back.

• A swimmer moves forward.

Multiple Choice

Which is the Reaction Force in this scenario: "A swimmer pushes back on the water and moves forward."

• A swimmer pushes back.

• A swimmer moves forward.

Example

A rocket blasting off from the launch pad.

Multiple Choice

Which is the Reaction Force in this scenario: "A rocket blasting off from the launch pad."

• A rocket blasting off from the launch pad.

• The thrust of the fuel against the launch pad.

Multiple Choice

Which is the Action Force in this scenario: "A rocket blasting off from the launch pad."

• A rocket blasting off from the launch pad.

• The thrust of the fuel against the launch pad.

Example

A fireman turns on a hose and is knocked backwards.

Multiple Choice

Which is the Action Force in this scenario: "A fireman turns on a hose and is knocked backwards."

• The force of the water from the hose.

• The fireman is knocked backwards.

Multiple Choice

Which is the Reaction Force in this scenario: "A fireman turns on a hose and is knocked backwards."

• The force of the water from the hose.

• The fireman is knocked backwards.

Open Ended

Brainstorm: Describe an example of Newton’s 3rd Law in your room.

Poll

Do you know Newton's 3rd Law?

• Yes.

• No, I need to learn more.

• Yes, and I want to learn more.

Open Ended

How can I make this lesson better? (Mentor Sentence: "You can make this lesson better by...")

Don't forget your homework!

Come to Small Groups to catch up on work!