Back To Course

AP Physics 1: Exam Prep13 chapters | 143 lessons | 6 flashcard sets

Are you a student or a teacher?

Try Study.com, risk-free

As a member, you'll also get unlimited access to over 75,000 lessons in math, English, science, history, and more. Plus, get practice tests, quizzes, and personalized coaching to help you succeed.

Try it risk-freeWhat teachers are saying about Study.com

Already registered? Login here for access

Your next lesson will play in
10 seconds

Lesson Transcript

Instructor:
*Angela Hartsock*

Angela has taught college Microbiology and has a doctoral degree in Microbiology.

In this lesson, we will learn how to use the slope of the line on a velocity vs. time graph to calculate the acceleration of an object in straight line motion.

The basic x, y graph has many interesting applications in physics and kinematics. In addition to succinctly describing the straight line motion of an object, you can use these graphs to calculate information like displacement, velocity, and acceleration. In this lesson, we'll continue our examination of the velocity vs. time graph and how it can be used to calculate the acceleration of an object in straight line motion.

You should be familiar with the velocity vs. time graph. This example graph illustrates how the velocity of a car changes as it drives along a straight track.

The equation for **acceleration** is *a = Î”v / Î” t*. Remember, when using an equation with a delta (Î”), you need to calculate the change: *Î” = final value - initial value*

So,

*Î”v = final v - initial v*

*Î”t = final t - initial t*

But, velocity (v) is on the y axis and time (t) is on the x axis. So, we could also write this equation as:

*a = Î”y / Î” x*

Does this look familiar? It should. This is the equation for the slope of a line on an x, y graph. So, the slope of a velocity vs. time graph gives the acceleration over that section of the graph. Confused? Let's look at an example.

This velocity vs. time graph shows the motion of a rat running in a long, straight tube.

First, the equation for acceleration is:

*a = Î”v / Î” t*

Let's fill in what we know:

*Î”v = 20 m/s - 0 m/s = 20 m/s*. His velocity started at 0 m/s and ended at 20 m/s so the change in velocity (Î”v) was 20 m/s.

*Î” t = 4 s - 0 s = 4 s*. The time started when he started moving (0 seconds) and we only care about the first 4 seconds, so his change in time (Î” t) was 4 s.

Filling in the equation, we get:

*a = (20 m/s) / (4 s) = 5 m/s^2*

His acceleration over the first 4 seconds was *5 m/s^2*. Remember, acceleration is a vector quantity and needs a directional component. In the case of straight line motion, the vector direction is equal to the sign of the magnitude. Since the *5 m/s^2* acceleration is positive, the vector direction is forward.

If we look at the last four seconds of the motion (*t* = 8*s* - 12*s*), the math is going to be nearly identical, but the change in velocity will be slightly different.

*Î”v = 0 m/s - 20 m/s = - 20 m/s*

If we substitute this into the equation, we get:

*a = (-20 m/s) / (4 s) = -5 m/s^2*

Notice that the sign is negative. This means the acceleration is negative and the rat is slowing down. The negative sign is our vector direction.

Let's briefly review.

You can use a velocity vs. time graph to calculate the acceleration of an object in straight line motion. The slope of a velocity vs. time graph gives the acceleration over a specific section of the graph. The equation for the slope of a line is *slope = Î”y / Î” x*

But, our axes have specific designations: y = velocity and x = time. Putting these together, we get the equation for **acceleration**: *a = Î”v / Î” t*

Remember, the sign of the acceleration represents the directional component required of vector quantities. A positive acceleration means the object is speeding up and a negative acceleration means it's slowing down.

Review this lesson to learn how to:

- Use a velocity vs. time graph to calculate acceleration
- Compare positive acceleration with negative acceleration
- Solve an example problem, keeping in mind that acceleration needs a directional component

To unlock this lesson you must be a Study.com Member.

Create your account

Are you a student or a teacher?

Already a member? Log In

BackWhat teachers are saying about Study.com

Already registered? Login here for access

Did you know… We have over 160 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

You are viewing lesson
Lesson
15 in chapter 3 of the course:

Back To Course

AP Physics 1: Exam Prep13 chapters | 143 lessons | 6 flashcard sets

- What is Kinematics? - Studying the Motion of Objects 3:29
- Scalars and Vectors: Definition and Difference 3:23
- What is Position in Physics? - Definition & Examples 4:42
- Distance and Displacement in Physics: Definition and Examples 5:26
- Speed and Velocity: Difference and Examples 7:31
- Acceleration: Definition, Equation and Examples 6:21
- Significant Figures and Scientific Notation 10:12
- Uniformly-Accelerated Motion and the Big Five Kinematics Equations 6:51
- Representing Kinematics with Graphs 3:11
- Ticker Tape Diagrams: Analyzing Motion and Acceleration 4:36
- What are Vector Diagrams? - Definition and Uses 4:20
- Using Position vs. Time Graphs to Describe Motion 4:35
- Determining Slope for Position vs. Time Graphs 6:48
- Using Velocity vs. Time Graphs to Describe Motion 4:52
- Determining Acceleration Using the Slope of a Velocity vs. Time Graph 5:07
- Understanding Graphs of Motion: Giving Qualitative Descriptions 5:35
- Free Fall Physics Practice Problems 8:16
- Graphing Free Fall Motion: Showing Acceleration 5:24
- The Acceleration of Gravity: Definition & Formula 6:06
- Projectile Motion: Definition and Examples 4:58
- Projectile Motion Practice Problems 9:59
- Kinematic Equations List: Calculating Motion 5:41
- Go to AP Physics 1: Kinematics

- Introduction to HTML & CSS
- Introduction to JavaScript
- Computer Science 332: Cybersecurity Policies and Management
- Introduction to SQL
- Computer Science 203: Defensive Security
- JavaScript Language Basics
- Forms & JavaScript
- JavaScript & HTML
- Error Handling, Debugging & Events in JavaScript
- HTML Elements & Lists
- What is the PHR Exam?
- Anti-Bullying Survey Finds Teachers Lack the Support They Need
- What is the ASCP Exam?
- ASCPI vs ASCP
- MEGA Exam Registration Information
- MEGA & MoGEA Prep Product Comparison
- PERT Prep Product Comparison

- Human Experience in Texts: Literary Features & Analysis
- System Calls: Function, Importance & Categories
- Multilingualism: Definition & Role in Education
- Supporting Adaptive Skills in Preschool
- Networking Components in Commercial Networks
- Managing Cybersecurity Risks through User Training, Awareness & Accountability
- Practical Application for C Programming: Recursive Functions
- Quiz & Worksheet - Stative Verbs
- Quiz & Worksheet - Significance of the Ganges River
- Quiz & Worksheet - Behavioral Theory & Learning Environments
- Quiz & Worksheet - Raising Reading Rate & Accuracy
- Flashcards - Measurement & Experimental Design
- Flashcards - Stars & Celestial Bodies
- Algebra 1 Worksheets
- Social Studies Essay Topics for Teachers

- Praxis Professional School Counselor (5421): Practice & Study Guide
- Project Management Training
- CLEP Principles of Management: Study Guide & Test Prep
- Business 314: Employment Law
- GCSE Physics: Practice & Study Guide
- Consumer Economics & Personal Finance
- CLEP Social Sciences and History: The Elizabethan Era
- Quiz & Worksheet - Sliding Friction
- Quiz & Worksheet - Methods for Teaching ELL Students
- Quiz & Worksheet - Prime Factorization
- Quiz & Worksheet - Ontology
- Quiz & Worksheet - Double Angle Properties & Rules

- The New Kingdom of Egypt: Pharaohs, Temples & Timeline
- Practical Application: Components of a Computer System Infographic
- How to Pass Microbiology
- High School Diploma Online Courses
- How to Pass the U.S. Constitution Test
- Study.com Demo for Enterprise
- Florida Teacher Certification Renewal
- Fieldtrip Checklist for Teachers
- How to Pass Intermediate Algebra
- How to Transfer Your Study.com Credit
- What is Professional Development for Teachers?
- What is a Digital Badge?

- Tech and Engineering - Videos
- Tech and Engineering - Quizzes
- Tech and Engineering - Questions & Answers

Browse by subject