Mechanical Engineering Interview Questions and Answers
Question - 1 : - What Is Extrued Aluminum?
Answer - 1 : -
- Extrusion is the process where a metal or a metal bar is pulled through a mandrel to elongate it and/or give it a final shape.
- Extruded Aluminum is a common form of making small aluminum wire, bars or beams and many varieties of small non-structural, decorative pieces.
Question - 2 : - What Is The Mechanical Advantage Of A Double Pulley?
Answer - 2 : - It only takes half the effort to move an object but twice the distance.
Question - 3 : - What Is Knurling?
Answer - 3 : - 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.
Question - 4 : - How Does Hydraulic Clutches Work?
Answer - 4 : - By using a non-compressible fluid, it acts like a solid push rod.
Question - 5 : - Why Is Over-pressurizing An Air Conditioning System Bad?
Answer - 5 : -
Overcharging a refrigeration or air conditioning system can result in an explosion. To avoid serious injury or death, never overcharge the system. Always use proper charging techniques. Limit charge amounts to those specified on the system equipment serial label or in the original equipment manufacturer's service information.
Overcharging the system immerses the compressor motor, piston, connecting rods, and cylinders in liquid refrigerant. This creates a hydraulic block preventing the compressor from starting. The hydraulic block is also known as locked rotor.
Continued supply of electricity to the system causes heat to build in the compressor. This heat will eventually vaporize the refrigerant and rapidly increase system pressure. If, for any reason, the thermal protector fails to open the electrical circuit, system pressure can raise to high enough levels to cause a compressor-housing explosion.
Question - 6 : - Will A Steel Cable Become Longer If It Is Heated While Under Load?
Answer - 6 : -
Even the heaviest steel cables stretch under load, whether they heat or not. Heating the cable will certainly elongate it. Friction caused by guides or pulleys can greatly increase the temperature of a cable under load.
You might consider the possibility of total failure if the heat is high enough and I am not sure but the cable might act in unpredictable ways when it fails. Applying heat to a steel cable under load is probably dangerous to your health and the health of anyone nearby.
When steel is heated, steel expands. It does not need to be under load. That is the reason that in the old days before advanced electronics and optics surveyors used chains rather than cables for measuring land. Had they used cable they would have gotten different measurements in summer and winter based on the difference in temperature and the coefficient of expansion of the material. The coefficient of expansion is a number that informs just how much a given material will expand or contract for a given change in temperature.
To find the coefficient of expansion and other interesting information consult a materials handbook, available in better libraries or your local college of engineering. Another example of expanding steel and the necessity for dealing with this characteristic is the overlapping slip joint found on bridges that allows horizontal structural members to expand and contract without damaging the bridge.
Question - 7 : - What Is The Congressional Space Medal Of Honor?
Answer - 7 : -
The medal was created in 1969, designed by Congress for "any astronaut who in the performance of his duties has distinguished himself by exceptionally meritorious efforts and contributions to the welfare of the Nation and mankind.
Question - 8 : - What Is The Law Of Thermodynamics?
Answer - 8 : - There are actually 3 Laws of Thermodynamics (the actual number is debatable, but the number ranges from 3-5, depending on your adding skills).
Question - 9 : - Is It The Stress That, Produces Strain Or Strain Produces Stress?
Answer - 9 : -
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.
Question - 10 : - How Does A Super Charger Work In A Car?
Answer - 10 : -
A supercharger is a used to increase the volume of air dragged into each cylinder per stroke.
In combustion engines, there are only really two ways to increase power, firstly increase the amount of fuel in the engine (either increase the displacement, or add more cylinders) or increase the amount of air in the engine (for a more effective explosion of the fuel)
Superchargers are powered by the engines crankshaft, which is connected usually by a belt drive. This rotational power turns a fan, which sucks air into the intake manifold similar in effect to turbochargers, with reduced lag. However, superchargers take more energy out the engine, so swings and roundabouts.