Mechanical Engineering Interview Questions
Q 1. What is the difference between Technology and Engineering?
Ans. Engineering is application of science.
Technology shows various methods of Engineering.
A bridge can be made by using beams to bear the load,by an arc or by hanging in a cable; all shows different technology but comes under civil engineering and science applied is laws of force/load distribution.
Q. 2 What is the difference between tensile strength and tensile modulus?
Ans. Tensile Strength:-
It is the ultimate capacity of the material to resist the tensile load regardless of deflection.
It is the measure of the stiffness of an isotropic elastic material. It is also called asYoung Modulus.
. It is defined as the ratio of the uni-axial stress over the uni-axial strain.
Q. 3 What is the difference between shear Strength and tensile strength?
Ans. Tensile strength is the strength in tension on the application of pulling force while shear strength is the strength against cutting shear force.
Q. 4 What is Mechanical Engineering?
Ans. Mechanical engineering is a branch of engineering in which we apply physics laws along with material science to accelerate the human process.
Q. 5 What is the difference between Yield Stress and Yield Strength?
Ans. Stress is a measure of internal resisting force(load) applied on a body per unit area.While Strength is a quantification of the ability to carry the load.
Yield stress and Yield strength of a material usually used as interchangeable according to the application of load. If load is low we will use yield stress but if load will be vary high we will use yield strength.
Q. 6 What is the honing of cylinder liners?
Ans. "Chris Marine"is the manufacturer of honing equipment.
The head of the honing device consists of four synchronized stones.
For the initial honing diamond stones are used to break up the hardened surface in the scuffed areas.
For the main honing very coarse and hard stones are used to produce a very desirable rough surface all over the liner.
The advantage, especially for the 2-stroke engines, is possibility to save the liner after a seizure, scuffing or blow-by or even to eliminate the ovality of the liner.
Another advantage is that it is possible to machine a rough liner wall to obtain a well oiled surface.
Q. 7 What type of cooling you will prefer for a 3-cylinder engine system?
Ans. Multi-Cylinder Engines are used for heavy load cosideration. So it is a heavy duty engine. We will prefer liquid or water cooling system for a 3-cylinder engine system.
Q. 8 What is the difference between weight and mass?
Ans. Mass is the measure of amount of matter that a body or object contain. It is measured in Gram or KG. Mass of a body remains constant in the whole universe.
Weight is the measure of force that how strongly gravity pulls to that matter. It is measured in kilogram meter per second square. Weight will be changed according to the change in gravitational acceleration.
Q. 9 Differentiate the terms center of mass and center of gravity.
Ans. Each body is made by small-small particles. These particles contains some mass also.
Center of mass of a body is a point where all the masses of particles are centered.
Center of gravity of a body is a point where the vector some of all the gravitational forces will act.
If gravity is uniform then both center of mass and center of gravity will be SAME.
Q. 10 Why I-section beam is preferred for heavy loading?
Ans. It provides less deformation on the application of load and it withstand higher bending moments on comparison of other shapes of the beam. It is easy to manufacture.
Mechanical Interview Question Part-2
Q. 11 Why Centrifugal Pump is not called as a Positive Displacement Type of Pump?
Ans. The Positive Displacement pump has more or less constant flow regardless of pressure while centrifugal pump has varying flow depending upon pressure or head.
Viscosity is constant for positive displacement pump where centrifugal pump have up and down value because the higher viscosity liquids fill the clearances of the pump causing a higher volumetric efficiency.
Q. 12 Why the centrifugal pump is called high discharge pump?
Ans. Centrifugal pump is a kinetic device.
The centrifugal pump uses the centrifugal force to push out the fluid. So the liquid entering the pump receives kinetic energy from the rotating impeller.
Due to centrifugal force the impeller accelerates the liquid to a high velocity, transferring mechanical energy to the liquid. So it discharges the liquid in high rate.
13. Why is stress considered important in a shaft?
The following types of stresses are prevalent in shafts:
1- At the outermost surface of the shaft the max shear stress occurs on the cross-section of the shaft.
2-At the surface of the shaft on the longitudinal planes through the axis of the shaft the maximum longitudinal shear stress will occurs.
3- At 45 degrees to the maximum shearing stress planes at the surface of the shafts the major principal stress occurs. It equals the maximum shear stress on the cross section of the shaft.
4- For certain materials where the tensile and compressive strengths are lower in measure as compared to the shear strength, then the shaft designing should be carried out for the lowest strengths.
5- All these stresses are of significance as they play a role in governing the failure of the shaft. All theses stresses get generated simultaneously and hence should be considered for designing purposes
Q. 14 Why don't we use a single turbine of required power instead multiple turbines in hydro power stations?
Ans. It is difficult to work with a single turbine than multiple turbines because the exhaust of one turbine is used as input two second turbine.so work input becomes less for multiple turbines than a single turbine for doing greater work.that why we find multiple turbines for power generation in dams.
Q. 15. What are the types of bearing on the basis of friction?
Ans. There are two types of bearing.
1. Friction Bearing 2. Anti Friction Bearing
Q. 16 What is the difference between heat pump and heat engine ?
Ans. HEAT ENGINE IS A DEVICE WHICH PRODUCES WORK WHILE TRANSFERRING HEAT FROM HIGHER TEMP. TO LOWER TEMP. WHEREAS IN HEAT PUMP WORK IS NEED TO SUPPLY TO TRANSFER HEAT FROM LOWER TEMP. TO HIGHER TEMP.
Q. 17 What are the best materials for gears?
Ans. Cast iron it has great impact strength and also self lubrication and phosphorus bronze is also better for gears.
Q. 18 Where is fixed a Governer in automobile?
Ans. Governer is a device which is used to regulate speed of an engine. Mostly a centrifugal governor is used in an automobile, when the speed is high height of its arms increases thus decreasing the area... which in turn allows more fuel to enter and vice versa.
Q. 19 Why gate valve is not suitable for throttling?
Ans. Gate valve is not suitable for throttling because it is difficult to control the flow due to valve design.And flow of fluid can be caused for the damage of the valve.
Q. 20 Describe mechanical engineering in your own words.
Ans. Mechanical engineering is one of the largest and broadest fields of technical study.
Mechanical engineers are concerned with the engineering systems used to control and transform energy to meet the needs of humanity.
In mechanical engineering, students develop an understanding of basic topics and fundamental principles upon which engineered systems are conceived and developed in a modern society.
It is an excellent foundation for a rewarding career in engineering, as well as for further study in business, law, medicine, and other professions that require a solid foundation in science and technology, and the ability to solve problems.
Satendra Saini (author) from India on September 13, 2014:
Hi vipin chourey. Its an honor for me to find readers like you. I will try my best to provide more and more the valuable knowledge and questions about mechanical engineering.
vipin chourey on September 13, 2014:
Thanks for this......with the help pf this i can understand more than i know
Satendra Saini (author) from India on September 11, 2014:
Ok Manas! I promise to provide you some more questions that will help you to get a good job. By the way thanks for liking and leaving a gentle comment.
Manas ranjan mohanty on September 11, 2014:
good question ,but needs some more question that help in interview.
thanx on July 30, 2014:
Very nice questeion job related mechanical engineering...thanx so much
Satendra Saini (author) from India on July 27, 2014:
Very soon I am going to publish another hub related to Automobile Interview questions.
Gaurav on July 26, 2014:
Dis is vry helpful fr us and plzz give some qsn which is related to automobile
vitalis bilauri on May 05, 2014:
big up and keep it up.
Satendra Saini (author) from India on May 03, 2014:
Thanks for going through this hub Ghufran Ullah!
Satendra Saini (author) from India on May 03, 2014:
Thanks Vijay! Very soon, I am going to upload questions based on MS.
Ghufran Ullah on May 03, 2014:
very important and interesting questions.. thanks for uploading such type of questions
vijay on May 02, 2014:
Hey dizz is really very good. Questions are really of good quality and useful. Please add some more questions on material science.
Satendra Saini (author) from India on April 20, 2014:
Thanks Vikram for going through this hub. As soon as possible, I will add some more interview questions.
Vikram p on April 19, 2014:
I'm glad that i visited this hub Good questions..! Add some more questions which are expected to ask in interview...
Satendra Saini (author) from India on March 06, 2014:
Thanks Akash ! I am glad, that you like this hub.Thanks again for reading and commenting.
akash tiwari on March 06, 2014:
Nice question which help us