Work, Power, Energy, Efficiency

CONCEPTS

Work is done when a force moves its point of application. It is measured in Joules

One Joule (J) = one Newton metre (1J = 1Nm)

Energy is the capacity to do work. This is also measured in Joules; work and energy are different facets of the same concept

Types of energy and changes from one type to another(chemical, elastic, gravitational potential energy

The principle of conservation of energy

Power is the rate of doing work, or the rate of using up energy

Power is measured in Joules/sec or Watts

Efficiency is the ratio of useful work done divided by the energy expended OR useful power output divided by power intake

LESSONS

Work done against gravity, leading to the concept of potential energy

Pulley experiments

finding personal power out put when climbing stairs

Impossibility of perpetual motion machines