Are actual and practical machines the same? If yes then is the output energy less than the input energy?

Asked by meera.singh2326 | 11th Sep, 2020, 01:10: PM

Expert Answer:

Actual and practical machines are same. 
Ideal and actual machines are different. 
In practice, ideal machines do not exist. 
Ideal machines are those whose parts are weightless and frictionless so that which there is no dissipation of energy in any manner. Its efficiency is 100%, i.e. the work output is equal to work input. 
In practice, it is not possible to obtain 100% efficiency because when the work is done by the practical machines the input energy gets lost in the form of heat energy. 
For better understanding check the difference between the ideal and practical machines. 

Ideal machine



Practical machine (Actual machines)



1. Efficiency is 100%.



1. Efficiency is less than 100%



2. Its parts are weightless, elastic and perfectly smooth.



2. Its parts are not weightless, elastic or perfectly smooth.



3. There is no loss in energy due to friction.



3. There is always some loss of energy due to friction.



4. Work output of such a machine is equal to the work input.



4. Work output is always less than the work input.

Answered by Shiwani Sawant | 11th Sep, 2020, 03:31: PM