1.1 Energy changes in a system, and the ways energy is stored before and after such changes

Energy stores and systems, Changes in energy, Energy changes in systems, Power

A system

an object or group of objects.

What changes when a system changes

the way energy is stored

8 stores of energy

magnetic, internal (thermal), chemical, kinetic, electrostatic, elastic potential, gravitational potential and nuclear

4 ways energy is transferred

heating, waves, mechanically and electric current

kinetic energy store

energy of a moving object

eg busses

gravitational potential energy store

The energy of an object at height.

eg a mug on a table

elastic potential energy

energy an object has when it is stretched or compressed

thermal/internal energy store

the total kinetic and potential energy of the particles in an object

chemical energy store

energy that can be transferred by chemical reactions

eg food/fuels

nuclear energy store

energy stored in the nucleus of an atom

magnetic energy store

energy a magnetic object has when it is near a magnet or in a magnetic feild

electrostatic energy store

energy a charged object has near another charged object

Describe all the energy changes when you stretch a rubber band

energy form your chemical energy store is transferred mechanically to the rubber band’s elastic potential store

kinetic energy(J) =

0\.5 × mass(kg) × speed(m/s)^2

elastic potential energy(J) = 0.5 × spring constant(n/m) × extension(m)^2

used to calculate the amount of elastic potential energy stored in a stretched spring (equation given)

g.p.e(J) =

mass(kg) × gravitational field strength(n/kg) × height(m)

change in thermal energy(J) = mass(kg) × specific heat capacity(J/kg/°C) × temperature change(°C)

calculates the amount of energy stored in or released from a system as its temperature changes

specific heat capacity is

the **amount of energy** required to raise the temperature of **one kilogram** of the substance by **one degree** Celsius

power(w) =

(energy transferred or work done(J)) /time(s)

temperature

the average energy

heat

the total energy

power is

the rate at which energy is transferred or the rate at which work is done

1 joule per second =

1 watt