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26 Dec 2025
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Forces and Motion Explained for Edexcel IGCSE Physics
Nat
@womanb
1 / 3
Velocity, Acceleration and Motion Graphs
Speed and acceleration are two different things that often get mixed up. Speed tells you how fast something's moving, whilst acceleration shows how quickly that speed is changing. The key formulas you'll need are: average speed = distance ÷ time, and acceleration = change in velocity ÷ time taken.
Distance-time and velocity-time graphs are your best friends for solving motion problems. The gradient (slope) of a distance-time graph gives you speed, whilst the area under a velocity-time graph tells you the total distance travelled. These graphs make complex motion problems much easier to visualise and solve.
Don't confuse mass and weight - they're completely different! Mass stays the same whether you're on Earth or the Moon, but weight changes because it depends on gravity. On Earth, weight = mass × 10 .
Quick Tip: Remember that acceleration can be negative - this just means something is slowing down, not speeding up!
Newton's Laws and Forces
Newton's three laws explain how forces affect motion, and they're simpler than they sound. First law: balanced forces mean no change in speed. Second law: unbalanced forces cause acceleration . Third law: forces always come in pairs - push a wall, and it pushes back with equal force.
Terminal velocity happens when falling objects reach their maximum speed. A skydiver falling spreads out to increase air resistance, whilst a streamlined object cuts through air more easily. The balance between weight pulling down and air resistance pushing up determines this maximum speed.
Hooke's Law shows that springs stretch proportionally to the force applied - double the force, double the extension. This works perfectly until you reach the elastic limit, where the spring becomes permanently damaged and won't return to its original shape.
Real-World Connection: Your car's stopping distance increases dramatically with speed because kinetic energy increases with the square of velocity!
Moments and Turning Effects
Moments explain why it's easier to open a door by pushing near the handle rather than near the hinges. The turning effect depends on both the force applied and the distance from the pivot point. The formula is: moment = force × perpendicular distance from the pivot.
The principle of moments keeps seesaws balanced and cranes stable. For any balanced object, the total clockwise moments must equal the total anticlockwise moments. If they're not equal, the object will start rotating in the direction of the larger moment.
Centre of gravity is the point where all the weight of an object appears to act from. When you hang any object, its centre of gravity will always end up directly below the suspension point - this is how you can find it experimentally.
Practical Tip: Momentum is conserved in collisions, meaning the total momentum before impact equals the total momentum after - this principle helps solve crash and collision problems!
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very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
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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
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This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
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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
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
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
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
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 apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Forces and Motion Explained for Edexcel IGCSE Physics
Nat
@womanb
Forces and motion form the backbone of physics, explaining everything from why your phone drops when you let go to how cars brake safely. These fundamental concepts help you understand the physical world around you and are essential for your... Show more
Velocity, Acceleration and Motion Graphs
Speed and acceleration are two different things that often get mixed up. Speed tells you how fast something's moving, whilst acceleration shows how quickly that speed is changing. The key formulas you'll need are: average speed = distance ÷ time, and acceleration = change in velocity ÷ time taken.
Distance-time and velocity-time graphs are your best friends for solving motion problems. The gradient (slope) of a distance-time graph gives you speed, whilst the area under a velocity-time graph tells you the total distance travelled. These graphs make complex motion problems much easier to visualise and solve.
Don't confuse mass and weight - they're completely different! Mass stays the same whether you're on Earth or the Moon, but weight changes because it depends on gravity. On Earth, weight = mass × 10 .
Quick Tip: Remember that acceleration can be negative - this just means something is slowing down, not speeding up!
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Newton's Laws and Forces
Newton's three laws explain how forces affect motion, and they're simpler than they sound. First law: balanced forces mean no change in speed. Second law: unbalanced forces cause acceleration . Third law: forces always come in pairs - push a wall, and it pushes back with equal force.
Terminal velocity happens when falling objects reach their maximum speed. A skydiver falling spreads out to increase air resistance, whilst a streamlined object cuts through air more easily. The balance between weight pulling down and air resistance pushing up determines this maximum speed.
Hooke's Law shows that springs stretch proportionally to the force applied - double the force, double the extension. This works perfectly until you reach the elastic limit, where the spring becomes permanently damaged and won't return to its original shape.
Real-World Connection: Your car's stopping distance increases dramatically with speed because kinetic energy increases with the square of velocity!
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Improve your grades
Join milions of students
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Moments and Turning Effects
Moments explain why it's easier to open a door by pushing near the handle rather than near the hinges. The turning effect depends on both the force applied and the distance from the pivot point. The formula is: moment = force × perpendicular distance from the pivot.
The principle of moments keeps seesaws balanced and cranes stable. For any balanced object, the total clockwise moments must equal the total anticlockwise moments. If they're not equal, the object will start rotating in the direction of the larger moment.
Centre of gravity is the point where all the weight of an object appears to act from. When you hang any object, its centre of gravity will always end up directly below the suspension point - this is how you can find it experimentally.
Practical Tip: Momentum is conserved in collisions, meaning the total momentum before impact equals the total momentum after - this principle helps solve crash and collision problems!
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What is the Knowunity AI companion?
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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
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Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
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
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
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 apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
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
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
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
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
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 apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user