8.PS.2-6-Lesson 2-Action-Reaction Forces in Everyday Life

​Lesson 2: Action-Reaction Forces in Everyday Life

By Jessica Freeman

Objective

Students will evaluate and describe real-world examples of action-reaction force pairs.

Vocabulary:

Contact Force – A force that requires objects to touch.

Noncontact Force – A force that acts without objects touching (like gravity or magnetism).

Multiple Choice

What kind of force is this?

• Contact Force

• Non-Contact Force

Multiple Choice

What kind of force is this?

• Contact Force

• Non-Contact Force

Multiple Choice

What kind of force is this?

• Contact Force

• Non-Contact Force

Multiple Choice

What kind of force is this?

• Contact Force

• Non-Contact Force

Multiple Choice

What kind of force is this?

• Contact Force

• Non-Contact Force

Multiple Choice

What kind of force is this?

• Contact Force

• Non-Contact Force

Multiple Choice

What kind of force is this?

• Contact Force

• Non-Contact Force

Multiple Choice

What kind of force is this?

• Contact Force

• Non-Contact Force

Multiple Choice

What kind of force is this?

• Contact Force

• Non-Contact Force

Multiple Choice

What kind of force is this?

• Contact Force

• Non-Contact Force

Contact and Noncontact forces

• If you push a box across the floor, you are applying a contact force. The friction that works against you is also a contact force.

• The gravity holding you to the Earth is a noncontact force. Magnetism and electric forces are other examples of noncontact forces.

Multiple Select

Which of the following are a contact force?

• Hitting a baseball

• a magnet moving a train

• you opening the car door

• Friction between a bike tire and the sidewalk

​What is Newton's 3rd Law?

• ​Newton's 3rd Law of Motion states that, "Whenever one object exerts a force on a second object, the second object exerts equal and opposite force on the first object.

​

• We call this the law of action/reaction

​Do forces act alone?

Some text here about the topic of discussion

​NO! We talked about forces acting in pairs in Newton's 1st and 2nd Law. Forces always act in pairs, this something we have to remember!

​

Using your white boards draw a force diagram of you sitting in your chair! Be ready to explain if you are called on! ​

​

Multiple Choice

Newton's 3rd Law of motion states that....

• A object in motion/rest stays in motion/rest until it is acted upon by an unbalanced force.

• Force is equal to the mass and the acceleration of an object.

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

Multiple Choice

How do forces act on an object?

• They usually act alone

• They act in pairs

​

https://www.youtube.com/watch?v=ZkVU-bj9bDk

​Newton's 3rd Law in space!

Newton's Third Law

​Action and Reaction forces: These two forces are equal in size and opposite in direction

​

Use your white boards to explain the action reaction pairs happening in the picture!​

​

Multiple Choice

How is this an example of Newton's Third Law?

• Only the ball is applying a force to the soccer players head

• Only the soccer players head is applying the force to the ball

• The are both exerting an equal force on each other

Multiple Choice

When a small car pushes a big truck, the truck applies an equal and opposite force on the car

• True

• False

Open Ended

David pushes the wall to the left with his finger. The wall pushes David to the right. What is the action force and what is the reaction force?

Open Ended

When the tennis ball is dropped and hits the ground why is it that the ball bounces back to you hand?

Multiple Choice

When a cannon fires a cannonball we observe Newton's third law. Which is the reaction force?

• The cannon moving forward

• the cannon moving backwards

• the cannonball moving backwards

• The cannonball moving forward

Multiple Choice

A book rests on a table.  The force of gravity pulls down on the book with a force of 20 newtons. What prevents the books from accelerating downward ?   

• The table presses back up on the book with an equal and opposite force of 20 newtons.

• The table presses back up with a force greater than 20 Newtons

• The tale and the book together are accelerating downwards at 9.8 m/sec2

• The inertia of the book holds it up

Multiple Choice

When Ronda Rousey got kicked in the face, What is the interaction pair?

• The foot and the face

• Ronda Rousey and media criticism 

• The foot and the air flow

• Ronda Rousey and the floor

Poll

How do we feel about Newton's Third Law of Motion

• I'm feeling great, because I'm a pro

• I'm a little confused but I think I pretty much have it figured out

• I'm lost... point blank period

• What class is this?

Fill in the Blank

For any action force, there is an opposite & _______________ reaction force.

Fill in the Blank

Forces always come in _______________________.

Multiple Select

Which of the images below show Newton's 3rd Law of Motion?

F = MA can help us take Newton's 3rd Law another step further in understanding motion!!

Dropdown

Which of Newtons 3 laws does a rocket use when it is thrust into space?​

Select answer

Multiple Choice

What force does your seat use against you when you are sitting in the roller coaster?

• Force of air resistance and force of buoyancy
• Force of tension and force of inertia
• Force of gravity and force of magnetism
• equal and opposite reaction force

Multiple Choice

An example of force pairs:

• The bat forces the ball right; the ball forces the bat right

• The bat forces the ball right; the ball forces the bat left

• nothing happens because the forces are equal

• The bat forces the ball right; the ball does nothing to the bat.

Multiple Choice

Which of the following options finishes the force pair statement?

• the pin pushes the bowling ball right.

• the pin has no effect on the ball

• the pin falls down

• the pin stops the ball because the forces are balanced

Multiple Choice

Does the image show an action/reaction force pair or a balanced force?

• action/reaction force pair

• balanced force

This is NOT a action/reaction force pair because the forces being applied are different and the forces are acting on the same object!

In this image the earth's gravity is pulling on the ball and the earth's normal (support) force is pushing on the ball. This is two forces acting on the same object!

downward

upward

forward

backward

backward

forward

strength

direction

Multiple Choice

If a bird hit your windshield on your car, the force of the car on the bird equals

• the force of the bird on your car.

• the force of the car on the brid

• an elastic collision on the windshield

• a noncontact force acting on the windshield

Multiple Choice

What is the net force?

• 3 N

• 3 N, right

• 17 N, right

• 3 N, left

Multiple Choice

What is the net force?

• 20 N 
• 0 N 
• 400 N 
• 40 N 

Multiple Choice

If these teams are pulling with the same amount of force what will happen?

• The boy in blue will win.
• They will not move at all.
• The boy in red will win.
• Both will fall down.

Multiple Choice

The forces in a force pair are in the _______ direction

• opposite

• same

Multiple Choice

Forces always act in equal and opposite pairs.

• Newton's 1st Law

• Newton's 2nd Law

• Newton's 3rd Law

Multiple Choice

A player hits a ball with a bat. The action force is the impact of the bat against the ball. The reaction force is...

• The grip of the player's hands on the ball

• the air resistance of the ball

• the force of the ball against the bat

Multiple Choice

What is the reaction force to a foot pushing down on the floor?

• The foot going through the floor

• The floor pushing back against the foot

• The floor breaking to the foot

Multiple Choice

The amount of matter in an object.

• Weight

• Gravity

• Volume

• Mass

Multiple Choice

The image is an example of ..........

• Friction

• Force pairs

• Motion

• Balanced forces

Multiple Choice

If you pushed on a wall with 50N of force, the force acting on you from the wall would be .........

• 10 N

• 30 N

• 50 N

• 100N

Multiple Choice

What is Newton's Third Law of Motion?

• an object at rest stays at rest, and an object in motion will stay in motion until an outside force acts upon it

• the acceleration of an object will be equal to the net force of an object divided by its mass

• an object that is not moving will stay not moving moving until an unbalanced force acts on it

• for every action, there will be an equal and opposite reaction

Multiple Choice

What is the net force?

• 20 N

• 400 N

• 0 N

• 40 N

Multiple Choice

Newton’s law states that for every action, there is an ________ reaction.

• unequal and opposite

• equal and similar

• stronger and opposite

• equal and opposite

Multiple Choice

When a small car pushes a big truck, the truck applies an equal and opposite force on the car.

• False

• True

Multiple Choice

When a cannon fires a cannonball we observe Newton's third law. Which is the reaction force?

• The cannon moving forward

• The cannon moving backwards

• The cannonball moving backwards

• The cannonball moving forward

Multiple Choice

Action reaction forces never cancel each other out because

• They act on different objects.

• They act on the same objects

• They do not act on objects.

Multiple Choice

How is this an example of Newton’s Third law?

• Only the ball is using the head

• They are both exerting an equal force on each other

• Only the head is pushing the ball

Multiple Choice

If two people with the same mass collide, they experience the same amount of force.

• True

• False

Multiple Choice

Action-reaction pairs can cause a change in motion.

• True

• False

Multiple Choice

Force always come in________

• waves

• triplets

• pairs

Multiple Choice

When a heavy football player and a light one run into each other, who exerts more force

• The light one

• Their force are equal

• The heavy one

Multiple Choice

The forces in a force pair are in _______ direction

• opposite

• same

Multiple Choice

A person steps out of the boat and onto the dock.  As the person moves forward onto the dock, the boat moves backward.  Which statement best describes the backward motion of the boat as the person steps forward?

• For every action there is an equal and opposite reaction.
• Every mass exerts a force on every other mass.
• An object at rest tends to stay at rest.
• Friction opposes the motion of an object.

Multiple Choice

Why is the net force 0 in the image?

• Because the elephants are the same size
• Because they are both pulling the same amount of force in opposite directions
• Because they are elephants
• Because they are pulling away from each other.

Multiple Choice

What will happen if the Action is greater than the Reaction?

• The man will fall

• The boat will sink

• Nothing will happen

Multiple Choice

What happens to the balloon if the air is released ?

• Balloon goes right

• Balloon goes up

• Balloon goes down

• Balloon goes left

Multiple Choice

if one object A exerts a force on a second object B, then B exerts a force on A, and the two forces are equal in magnitude and opposite in direction

• true

• false

Multiple Choice

Are you pulling on the earth

• yes

• no

• maybe

• depends on how i'm feeling

Multiple Choice

Which ISN'T part of newton's 3rd law

• Jumping off the ground

• Hitting a baseball

• Rain in the sky

• A car sitting on the road

Multiple Choice

A book pushes down on a table with a force of 5N, the table..

• Pushes back with a force of 5N

• Pushes back with a force less than 5N

• Pushes back with a forcec greater than 5N

• Does nothing. A table has no force.

Multiple Choice

Newton's are the unit used to measure...

• energy

• force

• weight

• mass

Multiple Choice

All forces occur in pairs

• true

• false