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ella
12/2/2025
Physics
Contact and Non-Contact Forces
45
•
Dec 2, 2025
•
Exploring Contact and Non-Contact Forces
ella
@eeetee
1 / 8
Contact and Non-Contact Forces
Ever wonder why things move or stop moving? It's all because of forces! Forces are responsible for every interaction between objects in our world.
Scientists divide forces into two main categories. Some forces need objects to be touching each other, while others can work across empty space. This simple classification helps us understand how everything from bicycles to planets works!
🔍 Think About It: Every time you interact with something today, try to identify what forces are at work. Is something pushing, pulling, or acting from a distance?
Contact Forces
Contact forces happen when objects physically touch each other. These are the forces you can often see and feel in everyday life.
When a baseball bat hits a ball, that's a contact force in action! Other examples include your shoes gripping the sidewalk as you walk and air pushing against an airplane's wings during flight.
Contact forces are easy to observe because you can usually see the objects interacting. This makes them a great starting point for understanding how forces work in our world.
Friction
Friction is a force that works against movement, always pushing in the opposite direction of motion. When you slide across a floor in socks, friction is what eventually stops you.
Friction can be helpful in many ways. It keeps you from slipping when you walk and allows your bike brakes to work. Without friction, simple activities like holding a pencil would be impossible!
However, friction has a downside too. It makes machines less efficient by wasting energy and creating unwanted heat. This is why engines need oil and why race cars are designed to minimize friction.
💡 Fun Fact: About 20% of the world's energy consumption goes to overcoming friction in mechanical systems!
Reducing Friction
Sometimes friction gets in our way, making things harder to move and wasting energy. Luckily, there are several clever methods to reduce unwanted friction.
Adding lubricants like oil or water creates a slippery layer between surfaces. That's why we oil bike chains and car engines! Bearings (those little metal balls inside skateboards and fidget spinners) also help by replacing sliding friction with rolling motion.
Making surfaces smoother, reducing an object's weight, and creating streamlined shapes all help reduce friction too. Engineers use these techniques to design everything from faster cars to more efficient machines that use less energy.
Non-Contact Forces
Have you ever been amazed by magnets that can move things without touching them? That's a non-contact force in action! These fascinating forces work across empty space without any physical connection.
There are three main types of non-contact forces. Magnetic forces make magnets stick to your refrigerator. Electrostatic forces create the shock you feel after shuffling across carpet. Gravitational forces keep your feet on the ground and the moon orbiting Earth.
Non-contact forces might seem magical, but they follow precise scientific laws. Understanding them helps explain everything from static-clingy clothes to the movement of planets!
🌟 Amazing Fact: Gravity is the weakest of all fundamental forces, yet it shapes our entire universe!
Magnetic Force
Magnetic force is the invisible push or pull that happens between magnetic materials. You've felt this force if you've ever played with magnets or stuck notes to a refrigerator.
Magnetic forces follow a simple rule: opposite poles attract while similar poles repel. That's why when you hold two magnets with their north poles facing each other, they push apart. But flip one magnet around, and they snap together!
This fascinating force works through space and even through some materials. The earth itself is like a giant magnet with north and south magnetic poles, which is why compasses work to help us navigate.
Electrostatic Force
Electrostatic force happens when electric charges interact. You've experienced this force if your hair has ever stood up after removing a hat or if you've gotten a tiny shock after walking across carpet.
Like magnets, electric charges follow a simple pattern: opposite charges attract each other (positive to negative), while like charges repel (positive pushes away positive; negative pushes away negative).
Electrostatic forces are surprisingly powerful! Lightning is a dramatic example of electrostatic forces in nature, where enormous amounts of opposite charges attract so strongly that electricity jumps through air.
⚡ Try It: Rub a balloon on your hair, then hold it near a thin stream of water from a faucet. Watch the water bend toward the balloon due to electrostatic force!
Gravitational Force
Gravitational force is what keeps your feet on the ground and makes dropped objects fall. It's the force of attraction between all objects that have mass.
Every object in the universe attracts every other object - that's gravity at work! The more massive an object is, the stronger its gravitational pull. Earth has a lot of mass, which is why everything on our planet is pulled toward its center with the familiar "plonk" when dropped.
Gravity works over enormous distances. It keeps the moon circling Earth and all the planets orbiting around the sun. Even though it's actually the weakest fundamental force in physics, gravity shapes the entire structure of our universe!
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.
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.9/5
App Store
4.8/5
Google Play
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
Exploring Contact and Non-Contact Forces
ella
@eeetee
Forces are all around us, making things move, stop, or change direction! They come in two main types: those that need objects to touch and those that work from a distance. Understanding these forces helps explain how almost everything in... Show more
Contact and Non-Contact Forces
Ever wonder why things move or stop moving? It's all because of forces! Forces are responsible for every interaction between objects in our world.
Scientists divide forces into two main categories. Some forces need objects to be touching each other, while others can work across empty space. This simple classification helps us understand how everything from bicycles to planets works!
🔍 Think About It: Every time you interact with something today, try to identify what forces are at work. Is something pushing, pulling, or acting from a distance?
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
Contact Forces
Contact forces happen when objects physically touch each other. These are the forces you can often see and feel in everyday life.
When a baseball bat hits a ball, that's a contact force in action! Other examples include your shoes gripping the sidewalk as you walk and air pushing against an airplane's wings during flight.
Contact forces are easy to observe because you can usually see the objects interacting. This makes them a great starting point for understanding how forces work in our world.
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
Friction
Friction is a force that works against movement, always pushing in the opposite direction of motion. When you slide across a floor in socks, friction is what eventually stops you.
Friction can be helpful in many ways. It keeps you from slipping when you walk and allows your bike brakes to work. Without friction, simple activities like holding a pencil would be impossible!
However, friction has a downside too. It makes machines less efficient by wasting energy and creating unwanted heat. This is why engines need oil and why race cars are designed to minimize friction.
💡 Fun Fact: About 20% of the world's energy consumption goes to overcoming friction in mechanical systems!
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
Reducing Friction
Sometimes friction gets in our way, making things harder to move and wasting energy. Luckily, there are several clever methods to reduce unwanted friction.
Adding lubricants like oil or water creates a slippery layer between surfaces. That's why we oil bike chains and car engines! Bearings (those little metal balls inside skateboards and fidget spinners) also help by replacing sliding friction with rolling motion.
Making surfaces smoother, reducing an object's weight, and creating streamlined shapes all help reduce friction too. Engineers use these techniques to design everything from faster cars to more efficient machines that use less energy.
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
Non-Contact Forces
Have you ever been amazed by magnets that can move things without touching them? That's a non-contact force in action! These fascinating forces work across empty space without any physical connection.
There are three main types of non-contact forces. Magnetic forces make magnets stick to your refrigerator. Electrostatic forces create the shock you feel after shuffling across carpet. Gravitational forces keep your feet on the ground and the moon orbiting Earth.
Non-contact forces might seem magical, but they follow precise scientific laws. Understanding them helps explain everything from static-clingy clothes to the movement of planets!
🌟 Amazing Fact: Gravity is the weakest of all fundamental forces, yet it shapes our entire universe!
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
Magnetic Force
Magnetic force is the invisible push or pull that happens between magnetic materials. You've felt this force if you've ever played with magnets or stuck notes to a refrigerator.
Magnetic forces follow a simple rule: opposite poles attract while similar poles repel. That's why when you hold two magnets with their north poles facing each other, they push apart. But flip one magnet around, and they snap together!
This fascinating force works through space and even through some materials. The earth itself is like a giant magnet with north and south magnetic poles, which is why compasses work to help us navigate.
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
Electrostatic Force
Electrostatic force happens when electric charges interact. You've experienced this force if your hair has ever stood up after removing a hat or if you've gotten a tiny shock after walking across carpet.
Like magnets, electric charges follow a simple pattern: opposite charges attract each other (positive to negative), while like charges repel (positive pushes away positive; negative pushes away negative).
Electrostatic forces are surprisingly powerful! Lightning is a dramatic example of electrostatic forces in nature, where enormous amounts of opposite charges attract so strongly that electricity jumps through air.
⚡ Try It: Rub a balloon on your hair, then hold it near a thin stream of water from a faucet. Watch the water bend toward the balloon due to electrostatic force!
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
Gravitational Force
Gravitational force is what keeps your feet on the ground and makes dropped objects fall. It's the force of attraction between all objects that have mass.
Every object in the universe attracts every other object - that's gravity at work! The more massive an object is, the stronger its gravitational pull. Earth has a lot of mass, which is why everything on our planet is pulled toward its center with the familiar "plonk" when dropped.
Gravity works over enormous distances. It keeps the moon circling Earth and all the planets orbiting around the sun. Even though it's actually the weakest fundamental force in physics, gravity shapes the entire structure of our universe!
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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4.9/5
App Store
4.8/5
Google Play
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