A mechanism is an assembly of different parts which perform a complete motion and is often part of a machine.
According to the Hess law the energy transfer is simply independent of the way being followed. If the reactant and the product of the whole process are the same then same amount of energy will be dissipated or absorbed.
3. Tell me what does a pump develop?
Pump is a device that is used to transfer fluid from one place to another place which means it develops flow not pressure.
4. Tell me the difference between projectile motion and rocket motion?
The major difference is that a projectile has no motor or a rocket on it, due to which the momentum is given to it as it is launched. A pen thrown across a room is a classic example of a projectile motion. On the other hand, a rocket or missile has a motor on it which helps in accelerating while moving. This helps in resisting other forces such as gravity. A projectile does not have any specific shape, it is a point mass, whereas rocket has a particular shape having its center of gravity situated at a particular point on its body. Thus rocket motion comes under kinetics and projectile comes under kinematics.
5. Tell me why re-heater is used in gas turbine?
The advantage of reheater is that it significantly increases the thrust; which is a prime reason for its use in gas turbines.
6. Tell me what is the percentage of carbon present in pig iron?
Carbon content is generally 3.5-4.5%.
7. Tell me what is GD&T and Who introduced the concept of GD&T?
GD&T is Geometric Dimensioning and Tolerancing .Its a language through which Design Engineers
communicate.Stanley Parker introduced the concept of Geometric Dimensioning and Tolerancing (GD&T) in 1930's and he was from Scotland.
8. Tell me if you are provided a bottle then how will you increase its strength?
The strength depends on design, material and thickness of the part. So in order to increase strength of the bottle one can provide the ribs and make the bottom of the bottle concave shaped. You can also increase its strength by using a stronger material and increasing its thickness.
9. Tell me the second law of thermodynamics?
The entropy of the universe increases over time and moves towards a maximum value.
10. Tell me what is the alloy of tin and lead?
A tin and lead alloy is commonly called solder. Usually solder is a wire with a rosin core used for soldering. The rosin core acts as a flux.
11. Tell us what is a uniformly distributed load?
A UDL or uniformly distributed load is a load, which is spread over a beam in such a way that each unit length is loaded to the same extent.
12. Tell me which conducts heat faster steel copper or brass?
Copper conducts heat faster than steel or brass. Any material that is good for conducting heat is also good for electricity in most cases. Wood terrible for transferring heat thus is also insulator for electric.
13. Tell me what is an ortographic drawing?
Orthographic projections are views of a 3D object, showing 3 faces of it. The 3 drawings are aligned so that if the page were folded, it would create part of the shape. It is also called multiview projections.
The 3 faces of an object consist of its plan view, front view and side view. There are 2 types of orthographic projection, which are 1st angle projection and 3rd angle projection.
14. Explain me is it the stress that, produces strain or strain produces stress?
A Force applied to an object will cause a displacement. Strain is effectively a measure of this displacement (change in length divided by original length).
Stress is the Force applied divided by the area it is applied. (E.g. pounds per square inch)
Therefore, to answer the question, the applied force produces both “Stress and Strain”. “Stress and Strain” are linked together by various material properties such as Poisson's ratio and Young's Modulus.
15. Tell me what are the points in the stress strain curve for steel?
Proportional limit, elastic limit or yield point, ultimate stress and stress at failure.
16. Explain Newton's three laws of Motion?
☛ The law of inertia: Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.
☛ Acceleration is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object). Force=Mass times acceleration.
☛ For every action there is an equal and opposite reaction.
17. Explain me what is a bearing? What are the different types of bearings?
Bearing is a device that helps smoother movement with minimal friction which in turn helps enhances efficiency and speed. Considering two types of loading, radial and thrust, there are different types of bearings which help handle these loads. The basic difference in the types of loads is essentially due to their ability to handle weight and different kinds of loads for various applications. Different types of bearings are:
☛ Ball bearing
☛ Roller bearing
☛ Ball Thrust bearing
☛ Roller thrust bearing
☛ Tapered roller bearing
☛ Magnetic bearings
☛ Giant Roller Bearing
Nikolaus Otto invented the four stroke engine. Both, two stroke and four stroke have their own advantages and disadvantages. 4 stroke is more fuel efficient. However, 2 stroke produces more power.
19. What is the types of sensors?
(i) Temperature Sensor- This device collects information about the temperature from a source and converts it to a form which is understandable by another device or person. Glass thermometer is the best example where mercury acts as the temperature sensor.
(ii) IR Sensors- This device detects and/or emits infrared radiation to sense a particular phase in the environment. Mostly thermal radiation is emitted by all the objects in the infrared spectrum. This type of radiation is not visible to the human eye but the infrared sensor detects it.
(iii) UV Sensors- These sensors measure the intensity of the ultraviolet radiation. This form of electromagnetic radiation has wavelengths which are longer than x-rays yet shorter than visible radiation. UV sensors can discover the exposure of environment to ultraviolet radiation.
(iV) Touch Sensor- A touch sensor acts as a variable resistor based on the location where it is sensed. Proximity Sensor- A proximity sensor detects the presence of objects that are placed in close proximity without any point of contact.
20. Explain how many types of suspensions are used in automobiles?
☛ McPherson struts
☛ Leaf spring
☛ Coil spring
☛ Torsion beam
☛ Wishbone
☛ Air Suspension
21. Tell me why is stress considered important in a shaft?
The following types of stresses are prevalent in shafts:
☛ > At the outermost surface of the shaft the max shear stress occurs on the cross-section of the shaft.
☛ > At the surface of the shaft on the longitudinal planes through the axis of the shaft the maximum longitudinal shear stress occurs.
☛ > At 45 degrees to the maximum shearing stress planes at the surface of the shafts the major principal stress occurs. It equals the max shear stress on the cross section of the shaft.
☛ > 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.
☛ > 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
22. Tell me what is the need of GD&T?
As we all know that its impossible to get a machine which gives you exact physical parts according to the required dimension. There is always some sort of deviation in the part manufactured. The deviations are caused due to following reasons:
☛ 1) Vibration in the machine
☛ 2) Tool Wear and Tear
☛ 3) Friction
☛ 4) Mounting Error
☛ 5) Human Error
☛ 6) Environment conditions.
So to meet the actual condition of machining tolerances and allowances are provided to the dimensions. So we require GD&T.
The metaphor here is to get the applicant to think about ALL of the different aspects in a certain phenomenon. The mindset that you are looking for is one that sees the bigger picture and can understand the various influencers in your product.
24. Tell me how does iron ore turn into steel?
To make Steel, Iron Ore is refined into iron and all the carbon is burned away using very high heat (Bessemer). A percentage of Carbon (and other trace elements) are added back to make steel. 36. What is knurling?
Knurling is a machining process normally carried our on a centre lathe. The act of Knurling creates a raised criss-cross pattern on a smooth round bar that could be used as a handle or something that requires extra grip.
25. Tell me what is a Newtonian fluid?
A Newtonian fluid possesses a linear stress strain relationship curve and it passes through the origin. The fluid properties of a Newtonian fluid do not change when any force acts upon it.
