rgy Learning objectives By the end of this chapter, you should be able to:
relate work and energy to each other state the law of conservation of energy list and give examples of the various forms of energy differentiate between potential and kinetic energy and use appropriate formulae for each
illustrate types of energy conversion describe the types and differences between renewable and non-renewable forms of energy
calculate the average power produced by humans and machines.
Work
Although there are many different ways in which we use the term ‘work’, in physics work is defined as what is accomplished by a given force moving an object a specific distance.
The formula for work is:
Work W = Fs
W = work ( J), F = force (N), s = displacement (m)
Work is a scalar quantity measured in joules (J), where 1 J = 1 N m (newton metre).
Energy
Energy and work are closely related. The law of conservation of energy is an important cornerstone of physics, as you will see throughout the course. Law of conservation of energy
Energy cannot be created or destroyed, but is converted from one form to another.
Energy is the ability to do work.
Work is the energy given to a body by a force moving it through a displacement in the same direction as the applied force.
