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Emma Corden
9/27/2025
Physics
forces in action
455
•
Sep 27, 2025
•
Newton's 2nd Law of Motion and Fun Physics Experiments for Class 9 and 11
Emma Corden
@emmacorden_rpll
1 / 8
Free Body Diagrams and Force Analysis
This page covers free body diagrams and provides examples of force analysis in various scenarios.
Key concepts:
- Free body diagrams use dots to represent objects and arrows to show forces.
- A detailed example of a helicopter lifting a mass is provided, demonstrating force calculations in different situations.
Highlight: When drawing free body diagrams, always use arrows to scale and a dot to represent the object.
Example: In the helicopter example, when the load experiences acceleration, the tension in the cable increases from 981N to 1081N.
Practical Investigation of Motion in Fluid
This page describes a practical investigation of motion in fluid and introduces forces on a slope.
Key points:
- The practical investigation involves dropping a ball bearing through a viscous fluid and measuring its motion.
- Forces on a slope are broken down into components parallel and perpendicular to the plane.
Vocabulary: Terminal velocity is the constant speed reached by an object falling through a fluid when the drag force equals the gravitational force.
Definition: The center of gravity is the point at which the entire weight of an object seems to act.
Moments and Force Analysis
This page introduces the concept of moments and provides examples of force analysis using trigonometry.
Key points:
- A moment is the product of force and the perpendicular distance from the pivot to the line of action of the force.
- The unit of moment is Newton-meter (Nm).
Definition: A moment is the turning effect of a force, calculated as the product of the force and the perpendicular distance from the pivot to the line of action of the force.
Example: For a force of 6N applied 0.1m from a pivot, the moment is 0.5 Nm.
The Principle of Moments and Force Couples
This page explains the principle of moments and introduces force couples and torques.
Key concepts:
- An object is in equilibrium when there is no net force acting on it and the sum of clockwise moments equals the sum of anticlockwise moments.
- Force couples consist of two equal and opposite forces acting in the same plane.
Definition: The principle of moments states that for an object in equilibrium, the sum of clockwise moments equals the sum of anticlockwise moments.
Vocabulary: A force couple consists of two equal and opposite forces acting in the same plane, creating a pure rotational effect.
Pressure in Fluids and Archimedes' Principle
This page covers pressure in fluids and introduces Archimedes' Principle.
Key points:
- Pressure in a fluid is calculated as P = F/A = mg/A = ρgh
- Archimedes' Principle states that the upthrust on a submerged object equals the weight of fluid displaced.
Definition: Archimedes' Principle states that the upthrust acting on a body submerged in a liquid is equal to the weight of the liquid that has been displaced.
Formula: Pressure in a fluid is given by P = ρgh, where ρ is density, g is gravitational acceleration, and h is depth.
Moments Practice Questions
This page provides practice questions on moments and their solutions.
Key points:
- Detailed solutions for moment calculations are provided, including trigonometric analysis.
- The principle of moments is applied to solve equilibrium problems.
Example: For a force of 5N applied at a 30° angle to a 0.2m lever arm, the moment is calculated as 5 × 0.1 = 0.5 Nm.
Highlight: When solving moment problems, always identify the perpendicular distance from the pivot to the line of action of the force.
Additional Moment Problems and Solutions
This page continues with more practice problems on moments and their detailed solutions.
Key points:
- A comprehensive problem involving a balanced beam is solved step-by-step.
- The principle of moments is restated and applied to find unknown weights and masses.
Example: In a balanced beam problem, the unknown weight is calculated to be 164 N, corresponding to a mass of 16.7 kg.
Highlight: When solving equilibrium problems, always equate the sum of clockwise moments to the sum of anticlockwise moments.
Forces in Action: Newton's Second Law
This page introduces Newton's second law of motion, which states that the net force acting on an object is equal to its mass multiplied by its acceleration .
Key points:
- One newton is defined as the force required to accelerate a 1 kg mass by 1 m/s².
- Various forces are discussed, including weight, upthrust, friction, and normal forces.
Definition: Newton's second law of motion states that F = ma, where F is the net force, m is mass, and a is acceleration.
Example: For a constant mass, if two forces of 2N upward and 1N downward are applied, the net force is 1N upward.
Vocabulary: Normal force is the force exerted by a surface on an object in contact with it, always perpendicular to the surface.
We thought you’d never ask...
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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
Newton's 2nd Law of Motion and Fun Physics Experiments for Class 9 and 11
Emma Corden
@emmacorden_rpll
Newton's Second Law of Motion and Fluid Mechanics: A Comprehensive Guide
This guide covers key concepts in physics, including Newton's 2nd law of motion, forces, free body diagrams, motion in fluids, moments, and pressure. It provides detailed explanations, examples,... Show more
Free Body Diagrams and Force Analysis
This page covers free body diagrams and provides examples of force analysis in various scenarios.
Key concepts:
- Free body diagrams use dots to represent objects and arrows to show forces.
- A detailed example of a helicopter lifting a mass is provided, demonstrating force calculations in different situations.
Highlight: When drawing free body diagrams, always use arrows to scale and a dot to represent the object.
Example: In the helicopter example, when the load experiences acceleration, the tension in the cable increases from 981N to 1081N.
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
Practical Investigation of Motion in Fluid
This page describes a practical investigation of motion in fluid and introduces forces on a slope.
Key points:
- The practical investigation involves dropping a ball bearing through a viscous fluid and measuring its motion.
- Forces on a slope are broken down into components parallel and perpendicular to the plane.
Vocabulary: Terminal velocity is the constant speed reached by an object falling through a fluid when the drag force equals the gravitational force.
Definition: The center of gravity is the point at which the entire weight of an object seems to act.
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
Moments and Force Analysis
This page introduces the concept of moments and provides examples of force analysis using trigonometry.
Key points:
- A moment is the product of force and the perpendicular distance from the pivot to the line of action of the force.
- The unit of moment is Newton-meter (Nm).
Definition: A moment is the turning effect of a force, calculated as the product of the force and the perpendicular distance from the pivot to the line of action of the force.
Example: For a force of 6N applied 0.1m from a pivot, the moment is 0.5 Nm.
Sign up to see the contentIt's free!
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Improve your grades
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The Principle of Moments and Force Couples
This page explains the principle of moments and introduces force couples and torques.
Key concepts:
- An object is in equilibrium when there is no net force acting on it and the sum of clockwise moments equals the sum of anticlockwise moments.
- Force couples consist of two equal and opposite forces acting in the same plane.
Definition: The principle of moments states that for an object in equilibrium, the sum of clockwise moments equals the sum of anticlockwise moments.
Vocabulary: A force couple consists of two equal and opposite forces acting in the same plane, creating a pure rotational effect.
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Improve your grades
Join milions of students
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Pressure in Fluids and Archimedes' Principle
This page covers pressure in fluids and introduces Archimedes' Principle.
Key points:
- Pressure in a fluid is calculated as P = F/A = mg/A = ρgh
- Archimedes' Principle states that the upthrust on a submerged object equals the weight of fluid displaced.
Definition: Archimedes' Principle states that the upthrust acting on a body submerged in a liquid is equal to the weight of the liquid that has been displaced.
Formula: Pressure in a fluid is given by P = ρgh, where ρ is density, g is gravitational acceleration, and h is depth.
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Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Moments Practice Questions
This page provides practice questions on moments and their solutions.
Key points:
- Detailed solutions for moment calculations are provided, including trigonometric analysis.
- The principle of moments is applied to solve equilibrium problems.
Example: For a force of 5N applied at a 30° angle to a 0.2m lever arm, the moment is calculated as 5 × 0.1 = 0.5 Nm.
Highlight: When solving moment problems, always identify the perpendicular distance from the pivot to the line of action of the force.
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Access to all documents
Improve your grades
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By signing up you accept Terms of Service and Privacy Policy
Additional Moment Problems and Solutions
This page continues with more practice problems on moments and their detailed solutions.
Key points:
- A comprehensive problem involving a balanced beam is solved step-by-step.
- The principle of moments is restated and applied to find unknown weights and masses.
Example: In a balanced beam problem, the unknown weight is calculated to be 164 N, corresponding to a mass of 16.7 kg.
Highlight: When solving equilibrium problems, always equate the sum of clockwise moments to the sum of anticlockwise moments.
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
Forces in Action: Newton's Second Law
This page introduces Newton's second law of motion, which states that the net force acting on an object is equal to its mass multiplied by its acceleration .
Key points:
- One newton is defined as the force required to accelerate a 1 kg mass by 1 m/s².
- Various forces are discussed, including weight, upthrust, friction, and normal forces.
Definition: Newton's second law of motion states that F = ma, where F is the net force, m is mass, and a is acceleration.
Example: For a constant mass, if two forces of 2N upward and 1N downward are applied, the net force is 1N upward.
Vocabulary: Normal force is the force exerted by a surface on an object in contact with it, always perpendicular to the surface.
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