Mechanical Engineering Questions -002

Mechanical Engineering Questions -002


1. What is the difference between steady and unsteady flow?

     In steady flow the velocity at a given point does not change with time whereas in unsteady flow it changes with time.

2. Define turbulent flow?

    Flow in which adjacent layers mix continuously, so that the flow pattern is unsteady, full of eddies, and apparently without any mathematically expressible regularity.

3. What is the difference between lower pair and higher pair?

    In a kinematic pair, if the elements have surface contact when in motion, the pair is called lower pair and if elements have line or point contact the pair is called higher pair.

4. What is the importance of the Thermodynamics in the field of Mechanical Engineering?

    All the mechanical engineering systems are studied with the help of thermodynamics. Hence it is very important for the mechanical engineers.

5. How many Laws of Thermodynamics are there? 

    There are three laws of the thermodynamics.

First Law: Energy can be neither created nor destroyed. It can only change forms. In any process in an isolated system, the total energy remains the same.

Second Law: It is not possible to transfer heat from lower temperature to higher temperature without using any external work done in a cycle.

We can say that it is not possible to make a heat engine which is 100% efficient.

Third Law: As temperature approaches absolute zero, the entropy of a system approaches a minimum.

6. What is Carnot engine?

It was being designed by Carnot and it is an imaginary engine which follows the Carnot cycle. We get maximum efficiency by using Carnot heat engine than any other engines.

7. What is Difference between stamina and strength?

  Strength is capability over a short length of time and Stamina is the ability to keep going continuously.

8. What is meant by One Ton Air-Conditioner?

  1 ton refrigerator extracts 210 kJ/min heat from the system.

10. What happens if gasoline is used in a Diesel Engine, Diesel Engine will work?

 No, it will not work, as the Compression ratio of Petrol engine is 6 to 10 & that of Diesel engine is 15 to 22. Thus on such high compression, gasoline gets highly compressed & it may blast.