Mechanical Engineering JOB Interview Questions, Why did you choose to study mechanical engineering?

Mechanical Engineering Interview Questions 

1.Why did you choose to study mechanical engineering?

This mechanical interview question gives the interviewer a chance to learn about the candidate’s interests in mechanical engineering. It helps reveal their passion for the field, and what interests them about engineering in general.

Do they want any job or are they looking to better society through quality engineering design? 

2. Talk about your first engineering design

By having mechanical engineering candidates talk about their early design work, hiring managers are able to better understand the engineer’s history in mechanical engineering.

They also gain insight into their thought processes and some of their favorite engineering designs.

3. What is the top skill a mechanical engineer must have?

This interview question gives the mechanical engineering interviewee a chance to explain what makes a great engineer.

There are a variety of answers you may receive. These answers include strong analytical skills, problem-solving skills, math skills, creative design skills, or strong knowledge of engineering fundamentals.

3. What is your CAD system of choice? And Why?

Do they prefer SolidWorks, CATIA, Inventor, or other CAD software? There is no wrong answer here and their experience with CAD software will depend on a lot on what industries they have worked in.

Different industries prefer CAD software systems that are more suited to their workflows and design processes. 

The interviewer will also get a chance to ask additional questions about the CAD software they have used. This will give the interviewer an opportunity to make sure the candidate has the CAD knowledge necessary for the job.

4. Name an engineering skill have you learned recently?

Good engineers are interested in learning new skills, computer programs, and ways to solve problems. Listen carefully to what the interviewee says to see if they have a love of learning new things and are adaptable to various situations.

Tell me about your most successful engineering project

This gives the mechanical engineer the chance to talk about their most successful engineering projects. Explain why they succeeded, what contributions they made to it, any technical skills that are used, and what they learned from the process.

5.Have you worked on an engineering project that failed?

Some of the greatest learning experiences come from failed projects. At some point when an engineer has worked on many projects, there are times that things don’t work out just right.

An engineer that can admit mistakes and learn from them has the potential to grow into a better engineer.

6. What mechanical engineering tasks interest you?

The only bad answer is saying “Any task”. Every engineer has engineering tasks they prefer over others, like solving equations, design engineering, building prototypes, testing, engineering analysis, or communicating the design.

This question gives you a chance to see if the main tasks the job calls for are ones the engineer enjoys doing.

7. Describe your process in checking for flaws

By asking this mechanical engineering interview question you will be able to get a better understanding of the mechanical engineer’s thought processes.

You can also gain insight into their daily workflows and problem-solving skills.

8. Do you prefer working alone or with an engineering team?

This mechanical engineering interview question can help determine if they work well with teams or are perhaps better suited for solo type projects and work.

Have you ever sent uncompleted engineering work to a client? If so Why? 

Companies and employees are often on tight deadlines to get work out the door. This can cause drawings and engineering work to be sent to a client which may be incomplete.

These sloppy methods can frustrate an engineer or manager that has to later clean up the mess.

9. How would you explain a complex design to a non-technical person?

An engineer that can explain complex ideas and engineering designs in easy-to-understand terms may be a good resource for a variety of reasons.

One of these is meeting with potential clients to win a bid.

They can also help a current client who’s been asking technical questions to understand the project engineering variables better.

Jobs in Mechanical engineering 2021 , Trending JOBS in Mechanical engineering 2021.

Trending JOBS in Mechanical engineering 2021.

Mechanical engineering is the oldest branch of engineering but now, it has come up with new trends that align with our current world. Here's what aspiring engineers need to know.

Mechanical engineering is no longer limited to a niche field and has descended into several other specializations that include CAD/CAM, AI & ML, IoT, etc.

Here are the new trends in mechanical engineering that aspiring engineers should know about:

1. CAD/CAM (Computer-aided design and computer-aided manufacturing)

CAD/CAM are software that use computer-based methods to encode geometrical data in which the processes of design and manufacture of automated machinery are highly integrated.

While CAD is mainly used to create designs, CAM is the control of machine tools in the manufacturing of parts.

The former helps designers and the latter helps reduce manufacturing costs. Both the software require powerful computers.

2. Design of heat exchanger

Heat exchangers are systems that work by transferring heat from one place to another between two or more fluids.

It is a system that facilitates heat transfer in an easy way without actually transferring the fluid directly. They are highly important parts of fuel cell systems for thermal management functions.

The mechanical engineering field has recently seen a lot of scope in designing energy-efficient, effective, lasting heat exchangers.

3. Smart manufacturing industry 4.0 and IoT (Internet of Things)

Smart manufacturing, easily put, is a manufacturing system that could have speed, structure, and accountability to resolve issues, to bring about a completely integrated, collaborative structure across all ends of the supply chain.

It ensures a real-time response, to meet the ever-growing demands in customer needs and the changing conditions of the supply network. It is called Industry 4.0 as it is the fourth industrial revolution in which the idea of smart manufacturing comes.

This smart industry has helped improve product quality, improve your asset utilization, etc. along with IoT, which is an interrelated system connecting devices, mechanical machines, people, objects, etc. to help transfer data over a network using UIDs (Unique Identifiers).

4. Artificial intelligence and machine learning

AI is the technology where a machine tries to simulate human behaviour. It is most definitely the future of every industry as AI is being used in most up-and-coming technological fields like robotics, VR, IoT, etc.

Machine Learning is one of the applications of AI which provides the system with automatic knowledge about a machine without having them explicitly programmed beforehand. ML also helps applications make better prediction outcomes.

Currently, some of the major industries recruiting for mechanical engineers include those involved in the fields of automobiles with hybrid and autonomous technology, data sciences, embedded systems, smart cities and urban analytics, etc. other than the above mentioned.

The future of mechanical engineering looks bright as several industries now require individuals with a strong sense of analytical skills and a deep understanding of evolving technologies in order to keep up with existing trends and set new standards in the industry.

What is Mechanical Engineering? Scope, Courses & Career opportunities also job chances in mechanical engineering.

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Fluid mechanics properties

FLUID PROPERTIES 

https://youtu.be/FJwzENDzhOc

Define fluid. 
A Fluid is a substance that deforms continuously when subjected to a shear stress no matter how small that shear stress may be.

Differentiate solid and fluid. 
Fluid
The fluid deforms continuously when subjected to a shear stress.
When the shear stress disappears the fluid never regain in to original shape. .
Solid

The Solid deforms a definite amount when subjected to a shear stress
When the shear stress disappears solids gain fully or partly their original shape.

Define density. 
Density is defined as the mass of a substance per unit volume.
If a fluid element enclosing a point P has a volume dV and dm , then the density is given by r = lim dV - 0 (dm / dV) = (dm / dV) The unit of density is kg/m3 .

Define specific volume,. 
Specific volume is defined as the reciprocal of density that is volume capacity per unit mass of fluid
Vs = ( 1 / r) = ( dV / dm ) The unit of sp. Volume is m3/kg

Define specific weight. 
Specific weight is the weight of the fluid per unit volume.
g = ( weight / volume) = ( m g / v) = r g The unit of specific weight is N/m3.

Define specific gravity (SG). 
Specific gravity is the ratio of mass density (or) weight density of the fluid to the mass density (or) weight density of the standard fluid. For liquids, water at 4oc is considered as standard fluid.
A liquid has a specific gravity of 1.527

what are the values of specific weight and specific volume ?
Specific gravity of a liquid (SG) = Sp. Weight (or) weight density of liquid / Sp. Weight (or) weight density of std liquid The standard liquid is water and its specific weight = r g = 1000 x 9.81 = 9810 N/m3
The specific weight of the liquid = 9810 x 1.527 = 14979.8 N/m3.
Density of the liquid ( r ) = 14979.8 / 9.81 = 1527 kg/ m3.
Specific volume of liquid = 1 /r = 1 / 1527 = 6.54 x 10 –4 m3/kg.

Define viscosity. 
The viscosity can be defined as the property of fluid which resist relative motion of its adjacent layers. It is the measure of internal fluid friction due to which there is resistance to flow, The unit of viscosity is Ns/m2.

State Newton’s law of viscosity. (AU-MQP)
The shear stress on a fluid element layer is directly proportional to the rate of strain (or) velocity gradient, the constant of proportionality being called the coefficient of viscosity.
t a (du / dy) shear stress ( t ) = m (du / dy)

what is real fluid ? Give examples. (AU-M03). 
The fluids in reality have viscosity m > 0 hence they are termed as real fluids and their motion is known as viscous flow. (ex) Air , water, kerosene, blood, milk

Why are some fluids are classified as Newtonian fluid ? Give examples of Newtonian fluids. (AU-N02).
The fluids, which obey Newton’s law of viscosity are known as Newtonian fluids. For these fluids, there is a linear relationship between shear stress and velocity gradient. (ex) Air, water, kerosene.

What is a Tthyxotropic fluid ? (AU- N 03)
If the viscosity increases with time the fluid is said to be a Thyxotropic fluid. (ex) Lipstick, paints enamels, crude oil.

What is a Rheopectic fluid ? 
If the viscosity decreases with time the fluid is said to be Rheopectic fluid. (ex) gypsum suspension, bentonite clay solution.

What is effect of temperature on viscosity of water and air ? 
*The viscosity of water decreases with increase in temperature.
*The viscosity of air increases with increase in temperature.

Define kinematic viscosity and gives its uint. 
Kinematic viscosity is defined as the ratio of dynamic viscosity to density.
n = m / r The unit of kinematic viscosity is m2/s

What is compressibility of fluid ? 
Compressibility of substance is the measure of its change in volume under the action of external forces, namely, the normal compressive forces. The measure of compressibility of the fluid is the bulk modulus of elasticity (K)
K = lim DV - 0 (- DP) / (DV/V) The unit of compressibility is N/m2

Assuming the bulk modulus of elasticity of water is 2.07 x 106 kN/m2 at standard atmospheric condition. Determine the increase of pressure necessary to produce one percent reduction in volume at same temperature. (AU-N02)
Bulk modulus of elasticity K = 2.07 x 106 kN/m2 - (dV/V) = 1% = 0.01
K = - dP / (dV/V) \ Increase in pressure dP = -(dV/V) x K
= 0.01 x 2.07 x 106 = 20700 kN/m2.

What is meant by vapor pressure of a liquid ? 
Liquids evaporate because of molecule s escaping from the liquid surface. These vapor molecules exert a partial pressure on the surface of the liquid known as vapour pressure.

What is cavitation ? 
In flowing fluid, if the pressure is equal to or less than the saturated vapor pressure, the liquid boil locally and produce vapor bubbles. These bubbles collapse in the high pressure region causing a partial vaccum. This phenomenon in known as cavitation.

Define surface tension and mention its unit. 
A free surface of the liquid is always under stretched condition implying the existence of tensile force on the surface. The magnitude of this force per unit length of an imaginary line drawn along the liquid surface is known as surface tension. The unit of surface tension is N/m.

Define capillarity. (AU-M04) 
Capillary implies the raise or depression of liquid in a capillary tube where it is held vertically or inclined in the liquid.

Define the pressure and mention its unit. 
If the fluid is stationary, then the force (dF) exerted by the fluid on the area is normal to the surface (dA). This normal force per unit area is called pressure..
P = ( dF / dA) The unit of pressure is N/m2.

What should be the depth of oil of specific gravity 0.8, if it has exerted a pressure of 480N/m2 ? 
Specific gravity (SG) = 0.8 \ density = 800 kg/m3
The pressure = r g z depth z = P/(r g) = 480 x 103 / (800 x 9.81) = 61.16 m
Express 3m of water head in cm of mercury.
rm gm Hm = rw gw Hw 13600 x Hm = 1000 x 3 Hm = 0.22 m of Hg

Differentiate between absolute and gauge pressure. 
Absolute pressure is measured as a pressure above absolute zero
Gauge pressure is measured as a pressure below atmospheric pressure
Gauge pressure = Absolute pressure - Atmospheric pressure

What do you mean by vacuum pressure ? 
If the pressure is less than the local atmospheric pressure it is called as vacuum pressure.
Vacuum pressure = Atmospheric pressure - Absolute pressure

What is a manometer ? Name the common fluids used in it. 
A manometer is a transparent tube containing a liquid of known density used for the purpose of measuring the fluid pressure. The common fluids used are mercury, alcohol.

Differentiate between simple manometer and differential manometer. 
Simple manometer
In simple manometer, one end is connected to the point at which the pressure is to be measured and the other end is open to atmosphere.

Differential manometer
In differential manometer, two ends are connected to the points whose ‘difference of pressure’ is to be measured.

What is micro-manometer ? Where is it used ? 
In this manometer a large difference in meniscus levels are obtained for very small pressure difference. This manometer is useful for precise measurement of pressure difference.

Design for Static and Dynamic Loading

Design for Static and Dynamic Loading

Machine parts fail when the stresses induced by external forces exceed their strength. The external loads cause internal stresses in the elements and the component size depends on the stresses developed.

Loading may be due to:

• The energy transmitted by a machine element.
• Dead weight.
• Inertial forces.
• Thermal loading.
• Frictional forces.

Load may be classified as:

• Static load- Load does not change in magnitude and direction and normally increases gradually to a steady value.

• Dynamic load- Load may change in magnitude for example, traffic of varying weight passing a bridge. Load may change in direction, for example, load on piston rod of a double acting cylinder. Vibration and shock are types of dynamic loading.

Avogadro’s number

Avogadro’s number

A mole is simply Avogadro's number of things. In chemistry, those "things" are atoms or molecules. In theory, you could have a mole of baseballs or anything else, but given that a mole of baseballs would cover the Earth to a height of several hundred miles, you'd be hard-pressed to find good practical use for a mole of anything bigger than a molecule [source: Hill and Kolb]. So if the mole is only used for chemistry, how did Amedeo Avogadro and chemistry cross paths  Born in Italy in 1776, Avogadro grew up during an important period in the development of chemistry. Chemists like John Dalton and Joseph Louis Gay-Lussac were beginning to understand the basic properties of atoms and molecules, and they hotly debated how these infinitesimally small particles behaved. Gay-Lussac's law of combining volumes particularly interested Avogadro. The law stated that when two volumes of gases react with one another to create a third gas, the ratio between the volume of the reactants and the volume of the product is always made of simple whole numbers. Here's an example: Two volumes of hydrogen gas combine with one volume of oxygen gas to form two volumes of water vapor (at least when temperatures are high enough) with nothing left over, or:

2H2 + O2 --> 2H2O

Tinkering around with the implications of this law, Avogadro deduced that in order for this to be true, equal volumes of any two gases at the same temperature and pressure must hold an equal number of particles (Avogadro's law). And the only way to explain that this law could be true for any example, including the one we just mentioned, is if there was a difference between atoms and molecules and that some elements, like oxygen, actually exist as molecules (in oxygen’s case, O2 rather than simply O) Granted, Avogadro didn't have words like "molecule" to describe his theory, and his ideas met resistance from John Dalton, among others. It would take another chemist by the name of Stanislao Cannizzaro to bring Avogadro's ideas the attention they deserved. By the time those ideas gained traction, the Italian with the crazy long name had already passed away.

So where does Avogadro's number fit into this? Because Avogadro's law proved so critical to the advancement of chemistry, chemist Jean Baptiste Perrin named the number in his honor. Read on to see how chemists determined Avogadro's number and why, even today, it's such an important part of chemistry.