Unit 2, Chapter 5

Integrated Science

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.

Chapter 5 Vocabulary Terms chemical energy

electrical energy

energy transformations

heat efficiency

horsepower

joule energy

kinetic energy

law of conservation of energy

nuclear energy

potential energy watt

power work

radiant energy

radiation

solar power

5.1 Work

W = F x dDistance (m)

Force (N)

Work (joules)

5.1 Work

Key Question:

What happens when you multiply forces in machines?

*Read text section 5.1

BEFORE Investigation 5.1

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

Ep = mgh Height (m)

Mass (kg)

Potential Energy (joules)

Accelerationof gravity (m/sec2)

5.2 Kinetic Energy

Ek = 1 mv2

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

5.3 Energy Transformations

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

Energy Transformations in a

Power PlantPower plants convert

chemical energy into electrical energy.

1. chemical energy2. heat energy3. mechanical energy4. electrical energy

5.3 Energy Transformations

Key Question:

Where did the energy go?

*Read text section 5.3 BEFORE Investigation 5.3