Conservation on energy

what is conservation of energy?

energy that cannot be created or destroyed but can only be transferred or transformed from one store to another

constant total energy

in a close or isolated system, the total amount of energy remains constant overtime

energy stores

energy is stored in different ways including kinetic , gravitational potential, elastic potential, chemical, magnetic, electrostatic, nuclear and thermal

closed system

a closed system is where no net change occurs to the total energy. total energy input equal total energy output and nothing enters or escapes the system

dissipation

energy that is not usefully transferred becomes wasted energy which is dissipated into the surroundings increasing the thermal energy

total energy equation

total energy in = useful energy out + wasted energy

energy store examples

skydiving, smartphones

reducing wasted energy

thermal insulation: wrapping an object in insulating material reduces unwanted heat transferring to surrounding eg a thick coat. lubrication: applying an lubricant like oil reduces friction decreasing amount of energy lost as thermal

unit for energy?

Joules (J)

an open system?

freely exchanges both energy and mass with its surrounding environment (boiling pot of water) : heat enters from stove while water vapor escapes into the air as steam )

kinetic energy

energy held by a moving object

gravitational potential

energy stored due to an objects position or height

elastic potential

energy stores when an object is stretched or squashed

thermal energy

energy related to an objects temperature

chemical energy

energy stored in chemical bonds like food fuels and batteries

magnetic energy

energy stores when magnetic objects interact

electrostatic energy

energy stored between interacting electrical charges

nuclear energy

energy stored deep inside the nucleus of an atom

how can energy transfer?

mechanically , electrically , heating , radiation

mechanically

by a force moving an object

electrically

by an electric current flowing

by heating

from a hotter object to a colder one

by radiation

using light or sound waves