Energy

Chapter 15 Section 1

Vocabulary

o Energy- is the ability to do worko Kinetic Energy- the energy of motiono Potential Energy- energy that is stored as a result of position or shapeo Gravitational potential energy- potential energy that depends upon an object’s height o Elastic potential energy- the potential energy of an object that is stretched or compressedo Mechanical Energy- the energy associated with the motion and position of everyday objectso Thermal Energy- The total potential & kinetic energy of all the microscopic in an objects o Chemical Energy- the energy stored in chemical bondso Electrical Energy- The energy associated with electric charges o Electromagnetic Energy- A form of energy that travels through space in the form of waves o Nuclear Energy- Energy stored in atomic nuclei.

Key Points

✓ How is gravitational potential energy determined?

An objects gravitational energy depends on its mass, its height and the acceleration due to gravity.

✓ What are the major forms of energy?

The major forms of energy are mechanical energy, thermal energy, chemical energy, electrical energy, electromagnetic energy, and nuclear energy

✓ How are energy and work related?

Energy and work are related because work is a transfer of energy.

✓ What factors does the kinetic energy of an object depend on?

The kinetic energy is any moving object depends upon its mass and speed.

Section 2

❖ Energy Conversion- is the process of changing energy from one form to another.

Key Points

▪ Can energy be converted from one form to another?

Energy can be converted to one form to another.

▪ What is the law of conservation energy?

The law of conservation energy of energy states that energy cannot be created nor destroyed.

▪ What energy conservation takes place as an object falls towards earth?

The gravitational potential energy of an object is converted to the kinetic energy of motion as the object falls.

▪ How are energy and mass related?

Einstein’s equation E=mc squared says that energy and mass are equivalent and can be converted into each other.

Extra Key Points

❖ Mechanical energy is the sum of an object’s potential energy and kinetic energy.❖ All chemical compounds, including fuels such as coal and gasoline, store energy.❖ A nuclear power plant uses nuclear fission reactions to generate electricity.❖ Nuclear fission is a process that releases energy by splitting nuclei apart.❖ A second type of nuclear reaction, nuclear fusion, releases energy when less massive nuclei

combine to form a more massive nucleus.

Section 3

• Non renewable energy resources- exist in limited quantities and once used cannot be replaced except over a course of million of years.

• Fossil fuels- oil, natural gas, and coal.

• Renewable energy resources- are resources that can be replaced in a relatively short period of time

• Hydroelectric energy- energy obtained from flowing water

• Solar energy-sunlight that is converted into usable energy

• Geothermal energy- is thermal energy beneath earth surface

• Biomass energy- the chemical energy stored in living things

• Hydrogen fuel cell- generates electricity by reacting hydrogen with oxygen

• Energy conversion- finding ways to use less energy or to use energy more efficiently.

Key points

❖ What are the major nonrenewable and renewable sources of energy?

The major nonrenewable resources are oil, natural gas, coal and uranium. The major renewable resources are hydroelectric, solar geothermal, wind, biomass, and possibly in the future nuclear fusion.

❖ How can energy resources be conserved?

Energy resources can be conserved by reducing energy needs and by increasing the efficiency of energy use.

Extra Vocabulary Chapter 15

★ Kinetic Energy (KE): KE=1/2MV squared ★ KE=Joules; M=Mass in kilograms; V=Velocity in meters per second ★ Potential Energy (PE): PE=MGH★ PE=Joules; M=Mass in kilograms; G=Gravity in 9.8m/s squared;

H=Height in meters★ Conservation of Mechanical Energy (ME): ME=KE+PE★ ME= Mechanical Energy in joules; PE=joules; KE=Joules

Einstein’s Equation E=MC squared

❏ Einstein’s Equation states that energy and mass are equivalent and CAN be converted into each other.

❏ C=speed of light in meters/second; M=Mass in kilograms

Extra Key Points

➔ Mechanical energy is the sum of an object’s potential energy and kinetic energy.

➔ All chemical compounds, including fuels such as coal and gasoline, store energy.

➔ A nuclear power point uses nuclear fission reactions to generate electricity. ➔ Nuclear fission is a process that releases energy by splitting nuclei apart. ➔ A second type of nuclear reaction nuclear fusion, releases energy when less

massive combine to form a more massive nucleus. ➔ When energy changes from one form to another, the total energy remains

unchanged even though many energy conservations may occur.

Extra Key Points

★ When work is done on an object, energy is transferred to that object.★ Mechanical energy does not include thermal energy, chemical energy, or other

forms of energy associated with the motion or the arrangement of atoms and molecules.

★ The sun radiates electromagnetic energy into space and is the source, either directly or indirectly of most of the world’s energy supplies.

Energy in Action