What do you understand by an ideal machine ? How does it differ from a...

An ideal machine is one that has weightless and frictionless components, meaning that there is no energy loss of any kind. The work output and work input are equal, making it 100% efficient. An ideal machine was initially envisioned as a mechanical system in which power and energy were neither wasted or lost due to friction or distortion. Energy intake and output are exactly equal. As a result, input=output may be used to represent it mathematically. The efficiency of a realistic machine is always less than 100% due to the second rule of thermodynamics, but the efficiency of an ideal machine should be 100%.
2 Although it is claimed that ideal machines contain weightless and frictionless sections, actual machines include weighted and frictional portions.