Question

What do you understand about an ideal machine? How does it differ from a practical machine?

Answer 1

We are asked about our understanding of the “ideal machine”. We can start by breaking down the question into two of its constituent words. That is, ideal and machine. Once we have done that we can simply understand what an ideal machine is. This gives us half the answer. For the other half we are asked to differentiate between the ideal machine and a practical machine.

Complete answer:
Let us start to attempt this question by breaking down the question into its constituent words and defining each of them individually. Ideal and machine, ideal means the ability of something or someone to do something in a hundred percent precision. Machine is an apparatus consisting of parts which have their own individual tasks. So, an ideal machine can be defined as one which has a hundred percent efficiency which means that the input work is the same as the output work. The parts of the machine must also be frictionless for this to happen.

Ideal machine	Practical machine
The efficiency of an ideal machine is one hundred percent	The efficiency is less than one hundred percent
The work output will be equal to the work input	The work output will be less than the input as it doesn’t have hundred percent efficiency
Since the parts are frictionless, there is no energy loss due to friction	There is energy loss due to friction as the parts are not frictionless
The parts are elastic, weightless and smooth	The parts aren’t elastic, weightless and smooth

Note:
Ideal machines have zero or no energy loss and the input work is always equal to the output work. One does not come across such a machine often. Hence practical machines are most commonly seen.