**Housekeeping:**We are now studying work, power and energy in physics. We will relate this content to the human body before we do the sports science unit. This unit's going to have some math in it, so keep calculators handy.

The science fair is coming. You need to start thinking about potential topics. I don't suggest doing plant projects because you will need at least 50 plants and one month to experiment with them. The best suggestion is to find past projects and revise them by changing the independent variable.

**Essential Idea:**Recognize how work and power describe how energy moves through the environment.

**Content Review:**

Links: Work, Energy & Power Work, Energy & Power II Simple Machines

**Student Missions:****Mission 1: ENERGY! Where the Power Lies!**

**Mission Objectives. You should be able to:**

1. Define "energy," "work," and "power."

2. Explain how energy, work and power are related.

3. Calculate work done.

4. Correctly calculate power used.

5. Design a lab to measure work, power and energy.

Energy as defined in physics is the ability to do work. Work is defined as the movement of a force over a certain distance. The energy of an object can take many forms: thermal energy (heat), chemical energy (chemical bonds), potential energy and kinetic energy. Potential energy is stored energy, or energy of position. Kinetic energy is energy of motion. Objects are either at rest or in motion, so, generally speaking, PE can equal KE.

The equation for potential energy is

The equation for kinetic energy is

Usually, we look at a combination of PE & KE, which, when combined, is mechanical energy (ME).

The equation for potential energy is

**m * g * h**. m is mass (kg), h is height (m), and g is gravity (9.8 m/s2).The equation for kinetic energy is

**1/2 m * v2**. m is mass (kg) and v is velocity (m/s).Usually, we look at a combination of PE & KE, which, when combined, is mechanical energy (ME).

Now let's talk about work. As stated above, work is defined as movement of an external force (F) over a particular distance (d). Work describes something that is being done to an object. The equation for work is Force (capital letter F) times distance. So Work = F*d. Force is measured in newtons (N) and distance is measured in meters (m). The unit Newton-meter (N*m) is better known as the joule (J).

Power is defined as work over time. The unit for power is the watt.

Power is defined as work over time. The unit for power is the watt.

Let's work some practice problems. You should be able to complete #1-20, Sample Problems #7-21, Work problems: #1, #4, #8-14, #16-19. We will review these in class.

**Mission 2: Machine's Way.**

**Mission Objectives. You should be able to:**

1. List and describe six simple machines.

2. Explain and determine mechanical advantage.

3. Analyze compound machines and describe them in terms of simple machines.

4. Calculate efficiency for simple and compound machines.

This is a lovely PowerPoint that takes you through all six simple machines, including mechanical advantage. If this does not satisfy your hankering for machine knowledge, you can also go here to learn more.

We will practice calculating mechanical advantage in class.

**Mission 3: Let's Build!**

Mission Objective. You should be able to...

Mission Objective. You should be able to...

1. Construct two simple machines that work.

Your project for this unit is to construct two simple machines. The machines must have a purpose and actually work. You need to be able to calculate the mechanical advantage for each machine. I will provide a rubric as soon as possible. You will work in six groups of three members each. You will be given some class time to construct the machines and you must provide your own materials.

Go here to find examples of each type of machine. This project is due April 17, 2018.