energy and power

energy

energy is the ability to do work

system

an object or group of objects working together

ten forms of energy

magnetic, kinetic, heat or thermal, light, Gravitational potential, Chemical, Sound, Elastic or strain potential, Electrical, Nuclear

8 energy stores

KInetic, Gravitational potential, Chemical, Elastic potential, Nuclear, Electrostatic, Magnetic, Thermal

a system is more efficient if

it transfers a greater proportion of the total input energy into useful output energy

dissipated

spreads out and transferred to the surroundings

energy cannot be

created or destroyed, it can only be transferred from one form to another

Kinetic energy

the energy an object possesses because of its motion

Gravitational potential energy

the energy stored in an object due to its position within a gravitational field

chemical energy

the potential energy stored in the atomic and molecular bonds of chemical compounds eg. batteries push electrons to create an electrical current

elastic potential energy

the mechanical energy stored inside an elastic object when work is done to stretch, bend or compress it

magnetic energy

a form of potential energy stored within a magnetic field or inside the bonds of magnetized materials

thermal energy

the internal energy of a system due to the random motion of its atoms and molecules

light energy

a form of kinetic and electromagnetic radiation made of tiny packets of energy

sound energy

a form of mechanical energy that results from the vibration of matter, traveling through a medium

electrical energy

the form of energy resulting from the flow or movement of electrical charges

nuclear energy

the energy stored in the core—or nucleus—of an atom, which can be released to generate large amounts of heat and electricity

kilo, K

1000 (x10³ )

mega, M

1,000,000 (x10⁶ )

giga, G

1,000,000,000 (x10⁹ )

terra, T

1000,000,000,000 (x10¹² )

unit of energy

Joules (J)

unit of power

Watts (W)

4 pathways

mechanical work, electrical work, heating, radiation

mechanical work

when a force moves through a distance

electrical work

when a charge moves through a potential difference

by heating

because of a temperature difference

by radiation

eg. light, microwaves, sound

a resource is renewable if

it is replenished (or can be) as fast or faster than it is used or will not run out

a resource is non-renewable if

it is not replenished as it is used, limited amount of it on earth

power

the rate of transfer of energy or the rate of doing work