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AP Physics 1AP Physics 1111 views·Updated May 19, 2026·2 pages

Describe

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priscilla@cilla

Motion in one dimension is all about tracking how objects... Show more

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Motion in One Dimension Describing motion •sign conventions for velocity: $V_x > 0$ motion to the right $V_y >D$ motion up $V_x <0$ motio

Describing Motion

When tracking motion along a single dimension, we use sign conventions to describe direction. For horizontal motion, positive velocity (Vx > 0) means moving right, while negative velocity (Vx < 0) means moving left. Similarly, for vertical motion, positive velocity (Vy > 0) means moving up, while negative velocity (Vy < 0) means moving down.

Position graphs show us where an object is at different times. The slope of a position graph tells us the velocity. Steeper slopes mean faster motion, while flatter slopes indicate slower motion. When a slope increases (gets steeper), the object is speeding up; when it decreases (gets flatter), the object is slowing down.

To interpret position graphs, follow three steps: first, determine position at a specific time by reading the y-axis; second, calculate velocity by finding the slope Δx/ΔtΔx/Δt; third, determine direction of motion from the sign of the slope positive=right/up,negative=left/downpositive = right/up, negative = left/down.

💡 Remember: When analyzing motion graphs, the shape matters! A straight line means constant velocity, while curves indicate changing speeds.

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Motion in One Dimension Describing motion •sign conventions for velocity: $V_x > 0$ motion to the right $V_y >D$ motion up $V_x <0$ motio

Uniform Motion and Instantaneous Velocity

For uniform motion (constant velocity), we can use three key equations: Vx = xf−xixf - xi/tf−titf - ti to find velocity, xf = xi + VxΔt to calculate final position, and Δx = VxΔt to determine displacement. These formulas help you predict where an object will be after moving at a constant speed.

Instantaneous velocity tells us how fast something is moving at a specific moment in time. On a position graph, it's the slope of the tangent line at that point. When the slope is zero (a horizontal tangent), the velocity is zero—meaning the object has momentarily stopped.

When looking at velocity graphs instead of position graphs, the displacement equals the area under the velocity curve. For example, if velocity increases steadily (forming a triangle), the displacement equals the area of that triangle.

🔍 Quick Tip: In a position vs. time graph, curves mean acceleration is happening. The steeper the curve, the greater the acceleration!

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AP Physics 1AP Physics 1111 views·Updated May 19, 2026·2 pages

Describe

user profile picture
priscilla@cilla

Motion in one dimension is all about tracking how objects move along a straight line. Understanding how to interpret position graphs and calculate velocities will help you solve physics problems and predict object movements.

1
of 2
Motion in One Dimension Describing motion •sign conventions for velocity: $V_x > 0$ motion to the right $V_y >D$ motion up $V_x <0$ motio

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Describing Motion

When tracking motion along a single dimension, we use sign conventions to describe direction. For horizontal motion, positive velocity (Vx > 0) means moving right, while negative velocity (Vx < 0) means moving left. Similarly, for vertical motion, positive velocity (Vy > 0) means moving up, while negative velocity (Vy < 0) means moving down.

Position graphs show us where an object is at different times. The slope of a position graph tells us the velocity. Steeper slopes mean faster motion, while flatter slopes indicate slower motion. When a slope increases (gets steeper), the object is speeding up; when it decreases (gets flatter), the object is slowing down.

To interpret position graphs, follow three steps: first, determine position at a specific time by reading the y-axis; second, calculate velocity by finding the slope Δx/ΔtΔx/Δt; third, determine direction of motion from the sign of the slope positive=right/up,negative=left/downpositive = right/up, negative = left/down.

💡 Remember: When analyzing motion graphs, the shape matters! A straight line means constant velocity, while curves indicate changing speeds.

2
of 2
Motion in One Dimension Describing motion •sign conventions for velocity: $V_x > 0$ motion to the right $V_y >D$ motion up $V_x <0$ motio

Sign up to see the content. It's free!

  • Access to all documents
  • Improve your grades
  • Join milions of students

Uniform Motion and Instantaneous Velocity

For uniform motion (constant velocity), we can use three key equations: Vx = xf−xixf - xi/tf−titf - ti to find velocity, xf = xi + VxΔt to calculate final position, and Δx = VxΔt to determine displacement. These formulas help you predict where an object will be after moving at a constant speed.

Instantaneous velocity tells us how fast something is moving at a specific moment in time. On a position graph, it's the slope of the tangent line at that point. When the slope is zero (a horizontal tangent), the velocity is zero—meaning the object has momentarily stopped.

When looking at velocity graphs instead of position graphs, the displacement equals the area under the velocity curve. For example, if velocity increases steadily (forming a triangle), the displacement equals the area of that triangle.

🔍 Quick Tip: In a position vs. time graph, curves mean acceleration is happening. The steeper the curve, the greater the acceleration!

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.

Most popular content in AP Physics 1

9

Most popular content

9

Can'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