Forces

​Balanced and Unbalanced Forces

By Yesenia Colon Irizarry

Learning Targets​

​I can . . . 

• Define the term force

• Contrast balanced and unbalanced forces

• Distinguish between contact and noncontact forces.​

• Calculate the net force on a free body diagram.

• Definition: Pull or push that creates movement.

• Is a vector.

• Unit of measurement is: 
  1 Newton (N) = 1 Kg x m/s²

• To change the movement of an object the force exerted needs to be greater than the force of the object. 

​

​Force

​Notebook Setup

Open Ended

What is a force?

Watch the video to understand there are forces everywhere on Earth.​

Let's watch a Video

Open Ended

What are some forces acting on you now that you can't see?

​Answer all the following questions for a grade!!

Multiple Choice

A contact force is from

• objects physically touching

• far apart objects

• not touching object

• always a pull

Multiple Choice

The three examples pictured are of

• Non-contact Forces

• Contact Forces

Multiple Choice

The force between the phone and the mount is a

• contact force

• non-contact force

Multiple Choice

Gravity is a

• Contact Force

• Myth

• Non-contact Force

Multiple Choice

Friction is a

• Contact Force

• Myth

• Non-contact Force

Multiple Choice

Magnetic Force is an example of ____________ force.

• contact

• non-contact

• balanced

• unbalanced

Multiple Choice

______________ is a force that always acts in the direction opposite of motion.

• applied

• friction

• gravity

• normal

Multiple Choice

Applied force is an example of a _________________ force.

• contact

• non-contact

• balanced

• unbalanced

Multiple Choice

You are pulled to the surface of the earth due to the force of _________________

• gravity

• friction

• normal force

• contact force

Multiple Choice

Which is an example of a non-contact force?

• elastic force

• normal force

• applied force

• electric force

Multiple Choice

What is gravity?

• A force
• Energy
• A push
• All of them

Draw

This person is pushing the box with a force of 450 Newtons.

Label the picture to show the direction and strength of the force.

Draw

Label the diagram correctly.

The person on the left is pulling with a force of 450 N and the person on the right is pulling with a force of 200 N.

Poll

Look at the picture.

Are the forces balanced or unbalanced?

• Balanced

• Unbalanced

Net Force & Free Body Diagrams Notes Start on the Next Slide

​Add the notes into your page

​This diagram shows four (4) forces acting on an object. There aren't always four forces.
For example, there could be one, two or three forces.

Draw

Practice #1: Draw the Free body Diagram for: A lamp is at rest on a tabletop. The Table exerts a force of 20N on the lamp.  Diagram the forces acting on the lamp, balanced or unbalanced, any movement? (Add this one to your graphic organizer/ practice).

Remember the object will be represented always by a square!!

Draw

Practice #2: A baby bird is free-falling from a nest in a tree.  Air resistance exerts a force on the bird of 5N.

Draw a free-body diagram showing the forces involved.

Add numbers where needed,

Calculate net force, direction of motion and if forces are balanced or not. 

Add this to your practice organizer.

Draw

Practice #3: A man drags a sled across loosely packed snow with a rightward acceleration. The man put 200 N of force, Friction is 100 N. The floor is exerting 100 N of force.   

Draw a free-body diagram, calculate the net force, identify the motion and describe if forces are balanced or unbalanced.

Add this to your notebook practice. 

Draw

Practice #4,5 and 6:  Calculate the force for the following situations (Add this to your notes Organizer)-Practice

Draw

Add what is missing,,, (add to your graphic organizer/ practice)

​Answer all the following questions for a grade!!

Multiple Choice

What is the net force?

• 5 N
• 45 N to the left
• 5 N to the right
• 45 N to the right

Multiple Choice

If there are two forces going in the SAME direction, you would ...?

• (-) Subtract the forces
• (+) Add the forces
• Neither
• (x) Multiply

Multiple Choice

What is the net force?

• 17 N Right
• 3 N Right
• 3 N Left
• 17 N Left

Multiple Choice

Look at the diagram. What would be the direction of the motion ?

• movement to the left
• movement to the right
• no movement

Multiple Choice

If there are two forces going in the opposite direction how would you find the net force?

• Subtract

• Add

• Neither

• Multiply

Multiple Choice

If both people are exerting a force of 30 N, what is the net force?

• 30 N

• 60 N

• 300 N

• 0 N

Multiple Choice

If the boy is pulling with a force of 10 N and the girl is pushing with a force 20 N, what is the net force on the box?

• 10 N

• 20 N

• 30 N

• 0 N

Multiple Choice

What is the net force on the object pictured?

• 3 N

• 5 N

• 4 N

• 8 N

Multiple Choice

Which direction will the object move?

• Up
• Down
• Right
• Left

Multiple Choice

The forces represented by the arrows in the diagrams are applied to the four objects that are at rest on a table. Which object is most likely to move to the right?

• Object W
• Object X
• Object Y
• Object Z

Multiple Choice

The forces represented by the arrows in the diagrams are applied to the four objects that are at rest on a table. Which object is most likely to remain in place?

• Object W
• Object X
• Object Y
• Object Z

Multiple Choice

How will this object move? 

• It won't move. 
• It will move to the right. 
• It will move to the left. 
• It will move in both directions. 

Multiple Choice

What is the magnitude (size) and direction of the net force?

• 15 N to the left
• 15 N to the right
• 1 N to the left
• 1 N to the right

Multiple Choice

What is the magnitude (size) and direction of the net force?

• 14 N Down
• 14 N Up
• 6 N Up
• 6 N Down

Multiple Choice

Calculate the Net Force. 

• 40N, Left
• 40N, Right
• 0N, Balanced
• 75N, Right

Multiple Choice

Calculate the Net Force.

• 1000 Newtons Up

• 9000 Newtons Up

• 1000 Newtons Down

• 9000 Newtons Down

Multiple Choice

What is the net force in this scenario?

• 5 Newtons Right

• 10 Newtons Right

• 15 Newtons Left

• 20 Newtons Left

Multiple Choice

How do you find the net force of this image.

• Add up all the arrows

• Add a green arrow and the orange arrow.

• Subtract all the arrows.

• Add the green arrows and subtract the orange arrow.