**Grade Level: **

9-12

**Prerequisites:**

9^{th} grade general math and science

**Concepts Addressed: **

In this unit, students will learn about the physical principles of speed, power, and torque.

Students will learn about DC motors and how these principles apply to them.

Students will apply these concepts on a sample mechanical system to calculate key details of the design.

**Learning Objectives: **

- The students will be able to explain the difference between speed, power and torque.
- The students will be able to demonstrate the concept of speed.
- The students will be able to demonstrate the concept of power.
- The students will be able to demonstrate the concept of torque.

**STEM Connections: **

The engineering process used in the real world for solving problems using the application of both practical and scientific information which will also follow a methodical process to develop the desired effect.

**Materials Needed: **

- Unit Guide
- Paper
- Pencils with erasers
- Rulers
- Internet Access
- Dictionaries
- VEX Robotics Kit
- Computers with Autodesk Inventor
- Storage containers
- Online Resources
- Engineering Notebooks
- Protractor
- Compass

**Key Terminology:**

- Methodical
- Engineering
- Mechanics
- Speed
- Rotational Speed
- Acceleration
- Force
- Work
- Power
- Torque
- Velocity
- Actuator
- DC Motor
- Voltage
- Current
- Stall
- Load

__Day to Day Lesson Plan:__

*Day 1:*

Provide students with the opportunity to look up the new vocabulary and to develop examples of speed, rotational speed, acceleration, and power. Allow for group discussion of terms.

You can provide additional information to correct and enhance the information that the students have gathered.

Cover the Following Topics from the Lesson Content:

Introduction

Engineering

Ask students what types of problems could be solved using the engineering process.

Ask students how they could use the engineering process to solve problems.

Classical Mechanics

Speed

Have students provide examples of speed.

Rotational Speed

Have students provide examples of rotation speed found in the classroom, the school, at home, and in the community.

Acceleration

Have students demonstrate the concept of acceleration

Force

Have students provide examples of how force is used in mechanics

Have students develop a demonstration the concept of force

*Day 2:*

Cover the Following Topics from the Lesson Content:

Torque

Allow the students time to work through math problems that support the classroom discussion on these topics.

Have students add the formula for torque to their engineering notebook for future reference.

*Day 3:*

Cover the Following Topics from the Lesson Content:

Work

Power

*Day 4:*

Cover the Following Topics from the Lesson Content:

DC Motors

Motor Loading

Current Draw

The Key Motor Characteristics

Varying Power with Voltage

Motor Limits & Calculations

*Day 5:*

Cover the Following Topics from the Lesson Content:

Arm Load Calculation

Torque Load Calculated from Current Limit

Motor Speed from Torque Load Calculation

Multiple motors

Work on calculations for voltage and motor limits.

*Day 6:*

Cover the Following Topics from the Lesson Content:

Arm Design

As part of the design process of a competition robot, it is possible a designer would use an arm structure similar to the ones that have been talked about earlier today.

*Day 7:*

Continue with Arm Design using VEX parts and or Autodesk Inventor

Check for detail in design

Check for integration of parts

*Day 8:*

Testing of arm designs. Data collection. Redesign.

Set up a location in the classroom where students can test their arm structures.

Check to see that data is recorded in Engineering Notebook.

Check for calculations used to make decisions on redesign.

*Day 9:*

Evaluation of arm structures.

Evaluation of the use of correct formulas and understanding of concepts presented in this unit.

Students can present their arm structures along with the explanation with formulas to the class.

*Day 10:*

Review concepts and formulas that were challenging for students.

**Engineering Notebook “Seed Questions”: **

- Why would you want to increase your speed and lower your power?
- Why would you want to increase your power and lower your speed?
- How does the change in the load affect your current draw?