Energy

Energy covers energy stores and transfers, the conservation of energy, kinetic and potential energy calculations, power, efficiency, energy resources and reducing unwanted transfers.

Learn the eight energy stores by name, since mark schemes expect the correct terms rather than descriptions. The core skill is tracking energy from one store to another and recognising that the total is conserved even when some is dissipated. Calculations dominate this unit — kinetic energy, gravitational potential energy, power and efficiency all appear regularly, and each rewards writing the equation, substituting, then rearranging rather than rearranging first. The most common errors are forgetting to square the velocity in the kinetic energy equation and mixing units, particularly kilowatts and watts. Efficiency answers should never exceed one hundred per cent.