# Ch 9: Praxis Physics: Rotational Motion, Collisions & Conservation

### About This Chapter

## Praxis Physics: Rotational Motion, Collisions & Conservation - Chapter Summary

Motion involving rotation can include a number of variables that affect angles and velocity. This collection of video lessons in the Praxis Physics review course provides an enjoyable way to look over these concepts as you get set to take the exam and get your certification. Along with rotational dynamics and torque, this chapter looks at the following topics:

- Translational vs. rotational motion
- The big five equations
- Rotational inertia
- Kinetic energy of rotation
- Rolling motion and the moment of inertia
- Work and power in rotational motion
- Angular momentum vs. linear momentum
- Equilibrium

The videos in this chapter include a timeline feature that lets you jump back and forth between lessons, enabling you to take each one at your own pace without worrying about losing your spot. A set of self-assessment quizzes will also give you a general idea of the kind of questions you can expect to see on the Praxis Physics exam.

### Praxis Physics: Rotational Motion, Collisions & Conservation - Chapter Objectives

The Praxis Physics exam is given to physics teachers earning their certification at different levels according to the states where they hold classes. Questions on rotational motion, collisions and conservation can be found in the Mechanics section of the test, which occupies about thirty-two percent of the exam's selected-response questions.

### 1. Differences Between Translational & Rotational Motion

After watching this lesson, you'll be able to explain the difference between translational and rotational motion, explain how translational quantities are replaced by rotational ones in physics and apply Newton's First Law to rotation. A short quiz follows.

### 2. Five Kinematics Quantities & the Big 5 Equations

After watching this lesson, you will be able to list the five kinematics variables in rotational motion and use the five equations of constant acceleration to solve problems involving rotational motion. A short quiz will follow.

### 3. Torque: Concept, Equation & Example

After watching this lesson, you will be able to explain what torque is conceptually and mathematically and use both the equation and Newton's First Law for rotation to solve problems involving torque. A short quiz will follow.

### 4. Rotational Inertia & Change of Speed

After watching this lesson, you will be able to explain what rotational inertia is, describe how it makes it harder to change the speed of rotation, and solve rotational inertia problems. A short quiz will follow.

### 5. Kinetic Energy of Rotation

After watching this lesson, you will be able to explain what kinetic energy of rotation is, provide the equation to calculate it, and solve simple kinetic energy of rotation problems. A short quiz will follow.

### 6. Rolling Motion & the Moment of Inertia

After watching this lesson, you should be able to figure out the moment of inertia of an object as it rolls down a ramp and compare it to a theoretical value. A short quiz will follow.

### 7. Work & Power in Rotational Motion

After watching this lesson, you will be able to explain what work and power are in the context of rotational motion and use equations to solve problems involving rotational work and power. A short quiz will follow.

### 8. Angular Momentum vs. Linear Momentum

After watching this lesson, you will be able to explain the difference between angular and linear momentum and solve problems using angular momentum equations. A short quiz will follow.

### 9. Conservation of Angular Momentum

After watching this video you will be able to explain what is meant by conservation of angular momentum. You will also be able to use this concept along with the equation to solve problems. A short quiz will follow.

### 10. Equilibrium: Translational & Rotational

Learn about the requirements for an object to be under translational or rotational equilibrium. Then work through a couple example problems that show how we can use translational and rotational equilibrium to find the forces acting on an object.

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### Other Chapters

Other chapters within the Praxis Physics (5265): Practice & Study Guide course

- Praxis Physics: Scientific Inquiry & Social Perspective
- Praxis Physics: Scientific Procedures & Techniques
- Praxis Physics: Vectors & Scalars
- Praxis Physics: Kinematics
- Praxis Physics: Motion
- Praxis Physics: Oscillations
- Praxis Physics: Work, Energy & Power
- Praxis Physics: Linear Momentum
- Praxis Physics: Laws of Gravitation
- Praxis Physics: Fluid Mechanics
- Praxis Physics: Electrical Forces & Fields
- Praxis Physics: Potential & Capacitance
- Praxis Physics: Direct Current Circuits
- Praxis Physics: Magnetism
- Praxis Physics: Optics & Waves
- Praxis Physics: Heat, Energy & Thermodynamics
- Praxis Physics: Modern Physics & Atomic Structure
- Praxis Physics: Content Knowledge Flashcards