Module 3: Description of Motion and Falling Bodies
Introduction
Motion is all around us on a vast range of scales: trees blowing in the breeze, people and animals walking and running around us, the sun and moon rising and setting, and a host of molecular processes that escape our sight. It is a primary goal of physics to explain these physical processes of our universe, and we begin this course by describing the basics of motion through mathematics that give us a preliminary description of the laws governing the many objects around us.
Learning Objectives
Upon completion of this module, students will be able to:
- Define displacement, velocity and acceleration.
- Differentiate between distance and displacement.
- Differentiate between velocity and speed.
- Be able to calculate distance, displacement, average velocity and speed from position and time information.
- Solve problems that involve the displacement, velocity and acceleration of a body.
- Graph equations of motion.
- Interpret graphs of equations and motion.
- Define kinematics.
- Integrate the understanding of the equations relating to displacement, velocity, and acceleration to calculate these quantities in examples of two-dimensional motion.
- Express understanding of displacement, velocity and acceleration with the use of practical examples.
To Do List
1. Watch the Video Lectures (links below)
2. Complete the Practice Problems (links below)
3. Take the Module 3 Quiz
4. Complete the Exam Practice Problems for Module 3
Lessons
Lesson 3.1 Displacement
An important distinction in physics is between the concepts of distance and displacement. Watch the video below to learn about the differences between these concepts and work on problems that will give you practice working out quantitative differences.
- Video: Distance as Displacement Links to an external site.
- Practice Problems Download Practice Problems
- Written Solutions Download Written Solutions
- Video Solutions:
- Extra Practice: Adding Displacements Download Extra Practice: Adding Displacements
- Test Your Understanding!
Lesson 3.2 Velocity
Now that we understand the physical definition of displacement, we can apply it in considering how far an object displaces during a given interval of time, also known as the velocity of the object. The video below provides and introduction to velocity and how it differs from the concept of speed.
- Video: Speed and Velocity Links to an external site. Trying to improve production values, we have remade the above video and the remade one is below. If you watch both (it's the same information) please answer the following one minute survey so that we know if we are improving the course!
- Student Feedback
- Video:Speed and Velocity-remade Links to an external site.
- Practice Problems Download Practice Problems
- Written Solutions Download Written Solutions
- Video Solutions:
- Test Your Understanding!
Lesson 3.3 Acceleration
In the same way that velocity is the rate of change of displacement, acceleration is the rate of change of velocity with respect to time. Acceleration is an extremely important concept that will be expanded upon in later sections to describe other fundamental aspects of physical motion such as force. The lecture videos below will describe the origin of acceleration and several examples are provided that show how to solve quantitative problems using displacement, velocity, and acceleration.
- Video: Introduction to Acceleration Links to an external site.
- Video: Basic Equations for Constant Acceleration Links to an external site.
- Demonstration 1,4,9,16, Ball-Drop Links to an external site.
- Example: Ball Drop Links to an external site.
- Example: Throwing a Ball in the Air Part 1 Links to an external site.
- Example: Throwing a Ball in the Air Part 2 Links to an external site.
- Video: Graphing Equations in Motion Links to an external site.
- Video: Interpreting Graphs of Motion Links to an external site.
- Practice Problems Download Practice Problems
- Written Solutions Download Written Solutions
- Video Solutions:
- Test Your Understanding!
Lesson 3.4 Expanding to Two-Dimensional Motion
The same basic principles of kinematics that we have discussed in the previous three sections can be applied to two dimensions as well. The same equations will be used, one for each dimension, and the problem, although slightly more complicated, can be solved in the same manner. Watch the lecture videos and examples below to understand how to solve these types problems.
- Video: Two-Dimensional Motion: Part 1 Links to an external site.
- Video: Two-Dimensional Motion: Part 2 Links to an external site.
- Demonstration: Ball Launcher Links to an external site.
- Demonstration: Two Ball Launcher Links to an external site.
- Example: Throwing a Ball from a Platform Links to an external site.
- Example: The Cannonball Links to an external site.
- Practice Problems Download Practice Problems
- Written Solutions Download Written Solutions
- Video Solutions:
- Test Your Understanding!
Quiz
Once you have watched the lectures and completed the practice problems, you should demonstrate your understanding by taking the Module 3 Quiz. Be sure to submit the quiz before its deadline.
Coming Up
In the next module we will learn about Newton's Laws.