Question

Discuss the differences between work and energy and why energy is conserved while work is not.

Answer 1

Firstly work is not a form of energy .. it is the measurement of the amount of energy that is transformed.
If a mechanical device is less than 100% efficient the useful work output is less than the work input .. just as the useful energy output is less than the input.
The 'missing',wasted energy (heat/sound) is created by the 'missing' work that has been done during the transfer.

If energy is conserved .. then it's measurement (work) is also conserved.