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Nov 27, 2025
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Understanding Different Types of Friction in Physics
Laura Tillman
@lauratillman
1 / 8
Helpful Static Friction
Static friction keeps objects from moving when they're at rest. Imagine your couch and lamp sitting perfectly still in your room—they stay put thanks to static friction!
This force acts between surfaces that aren't moving relative to each other. Without it, everything in your room would slide around like you're living on an ice rink.
Static friction creates stability in our world, preventing objects from sliding when we don't want them to move.
Try This: Place a book on a slightly tilted surface. The book stays in place until the angle becomes steep enough to overcome static friction!
Unhelpful Static Friction
Sometimes static friction works against us. When you try to lift weights off the ground, static friction makes the job harder by resisting the initial movement.
The weights want to stay put on the ground due to static friction. This means you need to apply extra strength to overcome this resistance and get the weights moving.
While static friction is great for keeping things stable, it can make starting movement more challenging when that's your goal.
Remember: Static friction only exists until movement begins—then it changes to sliding friction!
Helpful Sliding Friction
Slamming on the brakes shows sliding friction at its most helpful. When you hit the brakes hard, your tires slide against the road, creating friction that helps stop your car quickly.
This type of friction occurs when two surfaces slide past each other. The rougher the surfaces, the greater the sliding friction and stopping power.
Sliding friction prevents accidents by allowing objects in motion to slow down and stop when needed.
Real-World Example: Without sliding friction between your shoes and the floor, you couldn't stop running quickly or make sudden turns in a basketball game!
Unhelpful Sliding Friction
A snail trying to move across the ground faces the challenge of sliding friction working against it. The friction between the snail and the ground makes movement difficult and slow.
As the snail tries to slide forward, friction continuously opposes its motion. This resistance explains why snails move so slowly despite their efforts.
In this case, sliding friction is an obstacle to efficient movement, making the snail's journey much more difficult.
Think About It: Can you think of other situations where sliding friction makes movement harder? Ice skaters actually try to minimize this type of friction!
Helpful Rolling Friction
Skateboarding is possible thanks to rolling friction! When wheels roll against the ground, they experience much less resistance than if they were sliding.
Rolling friction occurs when an object rolls over a surface instead of sliding. This type of friction allows for smooth movement while still providing enough grip for control.
The wheels on a skateboard convert what would be sliding friction into rolling friction, making it much easier to move quickly and efficiently.
Fun Fact: Rolling friction is about 100 times less than sliding friction, which is why we put wheels on suitcases, cars, and skateboards!
Unhelpful Rolling Friction
When a pool ball gradually slows down and stops rolling, that's rolling friction at work. The slight texture of the pool table creates resistance against the ball's motion.
Even though rolling friction is less than sliding friction, it still exists. Over time, this friction converts the ball's energy of motion into heat until the ball stops completely.
Without perfect conditions, rolling friction will eventually slow down any rolling object—which isn't helpful when you want something to keep moving.
Challenge Question: Why do you think pool tables are covered in felt rather than a rougher material?
Helpful Fluid Friction
Airplanes rely on fluid friction to fly! As a plane moves through the air, fluid friction (also called drag) helps create lift that keeps the plane from falling.
Fluid friction occurs when objects move through liquids or gases. The shape of an airplane's wings uses this friction to generate upward force while minimizing resistance.
Without this type of friction, flight as we know it wouldn't be possible. The interaction between the plane and the air keeps it safely aloft.
Science Connection: Birds have evolved wing shapes that perfectly balance fluid friction forces—engineers designed airplane wings based on this natural example!
Unhelpful Fluid Friction
Slipping on ice happens because fluid friction can be treacherous. When someone slips, it's often because a thin layer of water on top of the ice creates very little friction.
The water acts as a fluid between the person's shoes and the ice, dramatically reducing grip. With almost no friction to provide stability, even a small force can cause a fall.
This demonstrates how reduced fluid friction can create dangerous situations when we need friction for stability and control.
Safety Tip: This is why we use salt on icy sidewalks—it melts the ice and creates a rough, slushy surface with more friction to prevent slipping!
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Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
Understanding Different Types of Friction in Physics
Laura Tillman
@lauratillman
Friction is a force that can either help or hinder movement in our everyday lives. This summary explores the different types of friction—static, sliding, rolling, and fluid—and shows when each type can be helpful or not helpful in real-world situations.
Helpful Static Friction
Static friction keeps objects from moving when they're at rest. Imagine your couch and lamp sitting perfectly still in your room—they stay put thanks to static friction!
This force acts between surfaces that aren't moving relative to each other. Without it, everything in your room would slide around like you're living on an ice rink.
Static friction creates stability in our world, preventing objects from sliding when we don't want them to move.
Try This: Place a book on a slightly tilted surface. The book stays in place until the angle becomes steep enough to overcome static friction!
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Unhelpful Static Friction
Sometimes static friction works against us. When you try to lift weights off the ground, static friction makes the job harder by resisting the initial movement.
The weights want to stay put on the ground due to static friction. This means you need to apply extra strength to overcome this resistance and get the weights moving.
While static friction is great for keeping things stable, it can make starting movement more challenging when that's your goal.
Remember: Static friction only exists until movement begins—then it changes to sliding friction!
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Helpful Sliding Friction
Slamming on the brakes shows sliding friction at its most helpful. When you hit the brakes hard, your tires slide against the road, creating friction that helps stop your car quickly.
This type of friction occurs when two surfaces slide past each other. The rougher the surfaces, the greater the sliding friction and stopping power.
Sliding friction prevents accidents by allowing objects in motion to slow down and stop when needed.
Real-World Example: Without sliding friction between your shoes and the floor, you couldn't stop running quickly or make sudden turns in a basketball game!
Sign up to see the contentIt's free!
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Unhelpful Sliding Friction
A snail trying to move across the ground faces the challenge of sliding friction working against it. The friction between the snail and the ground makes movement difficult and slow.
As the snail tries to slide forward, friction continuously opposes its motion. This resistance explains why snails move so slowly despite their efforts.
In this case, sliding friction is an obstacle to efficient movement, making the snail's journey much more difficult.
Think About It: Can you think of other situations where sliding friction makes movement harder? Ice skaters actually try to minimize this type of friction!
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Helpful Rolling Friction
Skateboarding is possible thanks to rolling friction! When wheels roll against the ground, they experience much less resistance than if they were sliding.
Rolling friction occurs when an object rolls over a surface instead of sliding. This type of friction allows for smooth movement while still providing enough grip for control.
The wheels on a skateboard convert what would be sliding friction into rolling friction, making it much easier to move quickly and efficiently.
Fun Fact: Rolling friction is about 100 times less than sliding friction, which is why we put wheels on suitcases, cars, and skateboards!
Sign up to see the contentIt's free!
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Improve your grades
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By signing up you accept Terms of Service and Privacy Policy
Unhelpful Rolling Friction
When a pool ball gradually slows down and stops rolling, that's rolling friction at work. The slight texture of the pool table creates resistance against the ball's motion.
Even though rolling friction is less than sliding friction, it still exists. Over time, this friction converts the ball's energy of motion into heat until the ball stops completely.
Without perfect conditions, rolling friction will eventually slow down any rolling object—which isn't helpful when you want something to keep moving.
Challenge Question: Why do you think pool tables are covered in felt rather than a rougher material?
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Helpful Fluid Friction
Airplanes rely on fluid friction to fly! As a plane moves through the air, fluid friction (also called drag) helps create lift that keeps the plane from falling.
Fluid friction occurs when objects move through liquids or gases. The shape of an airplane's wings uses this friction to generate upward force while minimizing resistance.
Without this type of friction, flight as we know it wouldn't be possible. The interaction between the plane and the air keeps it safely aloft.
Science Connection: Birds have evolved wing shapes that perfectly balance fluid friction forces—engineers designed airplane wings based on this natural example!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Unhelpful Fluid Friction
Slipping on ice happens because fluid friction can be treacherous. When someone slips, it's often because a thin layer of water on top of the ice creates very little friction.
The water acts as a fluid between the person's shoes and the ice, dramatically reducing grip. With almost no friction to provide stability, even a small force can cause a fall.
This demonstrates how reduced fluid friction can create dangerous situations when we need friction for stability and control.
Safety Tip: This is why we use salt on icy sidewalks—it melts the ice and creates a rough, slushy surface with more friction to prevent slipping!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
Where can I download the Knowunity app?
You can download the app in the Google Play Store and in the Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
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The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user