A3: Work, energy and power

Work done

the product of the force applied and the displacement in the direction of the force

Principle of conservation of energy

energy cannot be created or destroyed but may be transformed from one form to another

Mechanical energy

The sum of the kinetic energy, gravitational potential energy and elastic potential energy in a body

Power

Rate of transformation of energy (P=W/t) / Rate of work done

Efficiency

The ratio of the useful energy (power) output to the total energy (power) input

Energy density

The energy produced per unit volume (JM-3) of a fuel

Work Done by Force F

Kinetic Energy

Change in Gravitational Potential Energy

Elastic Potential Energy Stored in Helical Spring

Power

Efficiency