Work done (Energy transferred)
Let's start with work done.
Work done=Force x Distance. The distance is the distance moved in the direction of the force. When the force and the distance are in the same direction, the calculation is easy. When the force is in one direction and the movement is in a different direction many people lose marks. Study this example. Its very useful to think of the phrase energy transferred when you see the term work done. Very often the work done on an object shows up as an increase in kinetic energy or gravitational potential energy of the object
In most examples the work done means that energy has been transferred to an object. However the examiners sometimes create questions which show that the energy transferred when the work is done is apparently lost. If you are asked to explain what has happened to the work say " it has transferred to the internal energy of the surroundings".
What is power
Power tells you how much work is done in 1 second. 200 Joules of work done ( or energy transferred ) in 1 second is twice as much power as 100 Joules of work done ( or energy transferred) in 1 second.