Balanced/Unbalanced Forces

• There are at least two forces acting on all objects at rest:

  • The objects weight due to gravity (pull towards the Earth)

Normal force (push from the surface holding the object up)​

Long Answer

Yes!

​Short Answer

Do forces act on objects “at rest”?

Example: person “at rest”​

These forces are balanced (weight and normal force are equal)

The person is “at rest”.

If the chair could not balance the force of gravity she would fall through.​

Balanced forces​

For forces to be balanced then:

• The magnitude (size) of the two forces must be equal.

• The direction of the two equal forces must be opposite.

The objects motion will not change.​

Open Ended

Give an example of a balanced force that you might experience in your everyday life!

Unbalanced forces​

When one force is bigger than another the forces are unbalanced.

This will cause:

• A change in motion 

  (start, stop, speed up or slow down)

• A change in direction

• A change in shape​

Multiple Choice

Which of these is an unbalanced force?

• Resting against a wall

• Standing on the ground

• Apple falling to the ground

• Lying in bed

Start/Stop moving

Acceleration/deceleration

Change in shape/direction

​UNBALANCED

Constant speed

OR

At rest

​

BALANCED

Multiple Choice

You and your dad are moving the couch from one side to another. Your dad pushes with a force of 35 N to the right and you push with a force of 25 N right. What is the net force on the couch?

• 60 N right
• 10 N left
• 60 n right
• 50 N left

Fill in the Blanks

Multiple Choice

What is the net force?

• 40 N left
• 0 N Balalnced
• 400 N right
• 40 N right

Multiple Choice

How will this object move?

• It will not move

• It will move in both directions

• It will move to the right

• It will move to the left

Multiple Choice

If forces are going in the same direction, you should

• add the forces                      

• subtract the forces

• multiply the forces               

• divide the net force

Multiple Choice

What is the net force?

• 1000 N upward

• 500 N right

• 40 N right

• 0 N

Multiple Choice

What is the net force?

• 900 N unbalanced right

• 900 N balanced right

• 0 balanced

• 0 unbalanced

​Net Force

​Net force is the total force acting on an object.

• Add the forces when they operate in the SAME direction.

Subtract the forces when they operate in DIFFERENT directions.

Multiple Choice

Calculate the Net force

• 7N

• 17N

• 3N

• 10N

Multiple Choice

Calculate the Net force

• 20N

• 10N

• 0N

Multiple Choice

Calculate the Net Force

• 10N

• 0N

• 15N

Multiple Choice

Are the forces acting on this object balanced or unbalanced?

• Balanced

• Unbalanced

Multiple Choice

Are the forces acting on this object balanced or unbalanced?

• Balanced

• Unbalanced

Multiple Choice

Are the forces acting on this object balanced or unbalanced?

• Balanced

• Unbalanced

Multiple Choice

Are the forces acting on this object balanced or unbalanced?

• Balanced

• Unbalanced

Multiple Choice

A cat shoving a glass off a table

• Unbalanced force

• Balanced force

Multiple Choice

What is the net force?

• 40 N left
• 0 N Balalnced
• 400 N right
• 40 N right

Multiple Choice

What is the net force?

• 400 N Up
• 400 N Down
• - 400 N Down
• 800 N Down

Multiple Choice

The overall force acting on an object after all the forces are combined is called a 

• net force
• unbalanced force
• balanced force