Types of Forces

Types of Forces

Get ready to learn about forces! Remember to copy all notes and examples that are written in COLOR . When you come across a question, be sure to refer back to your notes!

What is a FORCE?

• A force is a PUSH or a PULL

• Forces are measured in a unit called NEWTONS

• You use a SPRING SCALE to measure force

• Forces are categorized into two groups: CONTACT or NON-CONTACT

Multiple Choice

What is the tool used to measure FORCE?

• balance

• spring scale

• weight

CONTACT FORCES

A force that can cause or change motion of an object by touching it. 

Examples of Contact Forces:

•Applied Force

•Normal Force

•Friction

•Air Resistance

CONTACT FORCES

The image shows a baker pushing his hands into dough, causing the top of the dough to accelerate downward. You can see the baker's hand and dough come into contact with each other. A contact force is a push or a pull applied by one object to another object that is touching it. Contact forces are also called mechanical forces. 

APPLIED FORCE

An applied force is when one object directly pushes or pulls on another. For example, pushing or pulling a door, texting or using a phone, writing, stirring a pot when you cook, a tug of war, etc. (Draw one example in your notes.)

Can you think of any other examples of an applied force?

NORMAL FORCE

A normal force is a support force that touches another object which is stable or not moving. For example, if a book is resting upon a surface like a table, then the surface is exerting an upward force upon the book in order to support the weight of the book. (Draw the picture in your notes.)

Can you think of any other examples of a normal force?

FRICTION

Why does the baseball player slow down as he is sliding towards home plate? FRICTION!

Friction is a contact force that resists the sliding or forward motion between two objects. The force of friction opposes motion, as seen by the blue arrow in the picture. Rougher surfaces will produce greater friction, while smoother surfaces reduce the force or friction.

Can you think of any other examples of friction?

FRICTION

Let's put this to the test.

1. Rub your hands together quickly for 15 seconds.

2. Next, apply hand sanitizer, water, or lotion to your hands.

3. Now, rub your hands together quickly for 15 seconds.

Did you notice a difference? What caused this to occur?

AIR RESISITANCE

Would you jump out of a plane without a parachute? Probably NOT!

Air resistance is a type of frictional force that acts upon objects as they travel through the air. As the canopy of the parachute opens, air gets trapped inside. The air pushes up on the parachute, while gravity is pulling you down. The opposing force of the air causes you to slowly fall.

QUIZ TIME!

Let's see how much you have learned.

Multiple Choice

What is the type of contact force that is being described?

A foot kicking a soccer ball

• Applied Force

• Normal Force

• Friction

• Air Resistance

Multiple Choice

What is the type of contact force that is being described?

The soccer ball slowing down as it rolls across the field.

• Applied Force

• Normal Force

• Friction

• Air Resistance

Multiple Choice

What is the type of contact force that is being described?

The soccer ball resting on the ground.

• Applied Force

• Normal Force

• Friction

• Air Resistance

Multiple Choice

What is the type of contact force that is being described?

Your hand being pulled backwards as you stick it out of the window of a moving car.

• Applied Force

• Normal Force

• Friction

• Air Resistance

Multiple Choice

What force are you demonstrating when you stand on the ground?

• Gravitational Force

• Friction

• Applied Force

• Normal Force

Multiple Choice

Are forces applied when the objects involved are in direct contact.

• Contact forces

• Normal forces

• action-at-a-distance forces

Multiple Choice

The upward force acting on the parachute is called ______________.

• Force of friction

• Force of gravity

• Normal force

• Air resistance

Multiple Choice

What force are you demonstrating when you pull a cup towards you?

• Gravitational Force

• Normal Force

• Applied Force

• Friction

Multiple Choice

What type of force is being applied to the car by the person?

• applied force

• normal force

Multiple Choice

What type of force is acting on the student and the chair?

• applied force

• normal force

• frictional force

Multiple Choice

This type of force is when one object pushes or pulls on another object by touching it

• Applied

• gravity

• magnetic

• normal

Multiple Choice

Is the force usually exerted by a surface on an object that is resisting against it.

• Friction

• Normal force

• applied force

• Tension

Multiple Choice

A type of friction that occurs when air pushes against a moving object causing it to decelerate.

• friction

• air resistance

• velocity

• gravity

Multiple Choice

Friction is a force that acts in an ___________ direction of movement.

• similar
• opposite
• parallel
• west

Multiple Choice

Leanna decided to rearrange her bedroom by moving her dresser to the opposite wall. She tried pushing it, but found that the dresser would not move. What force was Leanne NOT able to overcome?

• electrical force
• magnetic force
• balanced force
• frictional force