Forms and uses of energy, energy transfer and effi
Chemical energy - is energy stored in fuel(including food). This energy is released when chemical reactions take place.
Kinetic energy - is the energy of a moving object.
Gravitational potential energy - is the energy of an object due to it's position.
Elastic(or strain) energy - is the energy stored in a springy object when we stretch or squish it.
Electrical energy - is energy transferred by an electric current.
Thermal (heat) energy - of an object is energy due to its temperature. This is partly because of the random kinetic energy of the paricles of the object.
Cars, buses, planes and ships all use energy from fuel. They carry their own fuel. Electric trains use energy from fuel in power stations. Electricity transfers energy from power stations to the train.
efficiency = useful energy transferred by the device/total energy supplied to the device.
energy supplied = useful energy delivered + energy wasted