Equations of motion are essential tools in physics that help... Show more
Physics42 views·Updated May 28, 2026·2 pagesMotion Equations for Physics - A2 Level Notes
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Pasindi Lahandapurage@pasindilahandapurage_kqvo
1
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Understanding the Equations of Motion
Before diving into the equations, let's clarify what each symbol represents. In physics, we use displacement (s) measured in meters, initial velocity (u) and final velocity (v) in meters per second, acceleration (a) in meters per second squared, and time (t) in seconds.
The first equation of motion comes from the basic definition of acceleration. Since acceleration is the rate of change in velocity, we can write it as a = /t. Rearranging this gives us Equation 1: v = u + at. This formula lets you calculate the final velocity when you know the initial velocity, acceleration, and time.
Equation 2 deals with displacement using average velocity. When an object accelerates, its velocity changes constantly. The average velocity is /2, so the displacement formula becomes s = t/2. This equation is particularly useful when you need to find displacement without knowing acceleration.
💡 Think of these equations as your physics toolbox. You don't need to memorize how they're derived - just know when to apply each one. The key is identifying which variables you have and which one you need to find.
Equation 3: s = ut + ½at² comes from combining Equations 1 and 2. You can also visualize this as the area under a velocity-time graph, where displacement equals the sum of a rectangle (ut) and a triangle (½at²).
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Completing the Motion Toolkit
The final equation of motion eliminates time from the variables. By substituting t = /a from Equation 1 into Equation 2, we get Equation 4: v² = u² + 2as. This powerful formula relates displacement directly to initial and final velocities without needing to know time.
These four equations of motion form a complete system for analyzing uniform acceleration problems. The beauty of this system is that you only need to know three variables to find the fourth. Just identify what information you have and what you're looking for, then select the appropriate equation.
Remember that these equations only apply to situations with uniform acceleration - where the rate of change in velocity remains constant throughout the motion. Most basic physics problems like free fall, projectile motion, and simple car acceleration fit this model.
⚠️ Always check your units before solving problems! Displacement should be in meters, velocities in m/s, acceleration in m/s², and time in seconds. Mixing units will lead to incorrect answers.
With practice, you'll quickly develop the intuition to select the right equation for any motion problem. Don't worry if it seems challenging at first - everyone improves with practice!
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Physics42 views·Updated May 28, 2026·2 pagesMotion Equations for Physics - A2 Level Notes
P
Pasindi Lahandapurage@pasindilahandapurage_kqvo
Equations of motion are essential tools in physics that help us analyze how objects move under uniform acceleration. These equations relate five key variables: displacement, initial velocity, final velocity, acceleration, and time. Understanding how to use them will help you... Show more
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Understanding the Equations of Motion
Before diving into the equations, let's clarify what each symbol represents. In physics, we use displacement (s) measured in meters, initial velocity (u) and final velocity (v) in meters per second, acceleration (a) in meters per second squared, and time (t) in seconds.
The first equation of motion comes from the basic definition of acceleration. Since acceleration is the rate of change in velocity, we can write it as a = /t. Rearranging this gives us Equation 1: v = u + at. This formula lets you calculate the final velocity when you know the initial velocity, acceleration, and time.
Equation 2 deals with displacement using average velocity. When an object accelerates, its velocity changes constantly. The average velocity is /2, so the displacement formula becomes s = t/2. This equation is particularly useful when you need to find displacement without knowing acceleration.
💡 Think of these equations as your physics toolbox. You don't need to memorize how they're derived - just know when to apply each one. The key is identifying which variables you have and which one you need to find.
Equation 3: s = ut + ½at² comes from combining Equations 1 and 2. You can also visualize this as the area under a velocity-time graph, where displacement equals the sum of a rectangle (ut) and a triangle (½at²).
2
of 2Sign up to see the content. It's free!
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Completing the Motion Toolkit
The final equation of motion eliminates time from the variables. By substituting t = /a from Equation 1 into Equation 2, we get Equation 4: v² = u² + 2as. This powerful formula relates displacement directly to initial and final velocities without needing to know time.
These four equations of motion form a complete system for analyzing uniform acceleration problems. The beauty of this system is that you only need to know three variables to find the fourth. Just identify what information you have and what you're looking for, then select the appropriate equation.
Remember that these equations only apply to situations with uniform acceleration - where the rate of change in velocity remains constant throughout the motion. Most basic physics problems like free fall, projectile motion, and simple car acceleration fit this model.
⚠️ Always check your units before solving problems! Displacement should be in meters, velocities in m/s, acceleration in m/s², and time in seconds. Mixing units will lead to incorrect answers.
With practice, you'll quickly develop the intuition to select the right equation for any motion problem. Don't worry if it seems challenging at first - everyone improves with practice!
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.
Similar Content
Most popular content: Uniform Motion
1Most popular content in Physics
9Most popular content
9Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.6/5App Store
4.7/5Google 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 SiOS 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 KlichAndroid 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.
AnnaiOS user