Energy Stores

When energy is transferred to an object, the energy is stored in one of the object's energy stores. The energy stores you need to know are: 

• Thermal Energy Stores
• Kinetic Energy Stores 
• Gravitational Potential Energy Stores
• Elastic Potential Energy Stores
• Chemical Energy Stores
• Magnetic Energy Stores
• Electrostatic Energy Stores
• Nuclear Energy Stores

A system is just a fancy word for a single object or a group of objects that you're interested in. 

When a system changes, energy is transferred. It can be transferred into or away from the system, between different objects in the system or between different types of energy stores. 

Closed systems are systems where neither matter nor energy can enter or leave. The net change in the total energy of a closed system is always zero.  

Work done is just another way of saying energy transferred. 

Work done can be done when current flows or by a force moving an object. 

Falling objects also transfer energy

1) When something is dropped from a height, it's accelerated by gravity. The gravitational force does work. 

2) As it falls, energy from the object's gravitational potential energy store is transferred to its kinetic energy store. 

3) For a falling object when there's no air resistance:

Energy lost from the g.p.e store= Energy gained in the kinetic energy store

Anything that is moving has energy in its kinetic energy store. 

Formulae:

Ek= 0.5 x m x v^2 

Ek= Kinetic Energy (J)

m= Mass (kg)

v= Speed squared (m/s)^2

Formulae: 

Ep= m x g x h

Ep= Gravitational potential energy (J)

m= mass (kg)

g= Gravitational field strength (N/kg)

h= Height (m) 

Formulae: 

Ee= 0.5 x k x e^2

Ee= Elastic Potential (J) 

k= Spring constant (N/m) 

e= Extension (m)