Unit 2, Chapter 5 Integrated Science

Unit Two: Work and Energy 4.1 Force and Machines 4.2 The Lever 4.3 Gears and Design Chapter 4 Machines and Mechanical Systems

Chapter 4 What does a machine do? A simple machine is a device that makes work easier.

Chapter 4 What is a machine? A simple machine does not do the work for you.

Chapter 4 If a machine doesn’t do work for you why use them? A simple machine spreads the work out to make it take less force.

Chapter 4 Simple Machines There are 6 types of simple machines — Lever — Incline plane — Screw — Wedge — Wheel and axle — Pulley

Chapter 4 Simple Machines How much of larger the output force is than the input force is called the Mechanical Advantage.

4.1 Mechanical Advantage MA = F o F i Output force (N) Input force (N) mechanical advantage

4.2 What is a Lever? A Lever is a machine that turns around a fixed point called a fulcrum. *Read text section 4.2 AFTER Investigation 4.2

Unit Two: Work and Energy 5.1 Work 5.2 Energy Conservation 5.3 Energy Transformations Chapter 5 Work, Energy and Power

Chapter 5 Learning Goals Calculate the amount of work done by a simple machine. Use units of joules to measure the amount of work done. Analyze the effects of changing force or distance in a simple machine. Calculate the efficiency of a machine. Calculate power in machines. Discuss perpetual motion machines.

5.1 Work W = F x d Distance (m) Force (N) Work (joules)

5.2 Power P = W t Time (sec) Work (joules) Power (watts)

5.2 Energy Energy is the ability to do work. Any object that has energy has the ability to create force. Energy is measured in the same units as work. A joule is a unit of force that acts over a distance.

5.2 Potential Energy E p = mgh Height (m) Mass (kg) Potential Energy (joules) Acceleration of gravity (m/sec 2 )

5.2 Kinetic Energy E k = 1 mv 2 2 Speed (m/sec) Mass (kg) Kinetic Energy (joules)

5.2 Energy Conservation Key Question: What is energy and how does it behave? *Read text section 5.2 BEFORE Investigation 5.2

5.2 Energy Conservation Energy can be transformed from one form to another but cannot be created of destroyed.

5.3 Energy Transformations Energy transformations occur between different types of energy. — radiant energy — electrical energy — chemical energy — nuclear energy

Energy Transformations in a Power Plant Power plants convert chemical energy into electrical energy. 1. chemical energy 2. heat energy 3. mechanical energy 4. electrical energy

5.3 Energy Transformations Key Question: Where did the energy go? *Read text section 5.3 BEFORE Investigation 5.3