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Calorific Value
What is Petrol Calorific Value?
arun govind neelan
- Dec 24th, 2009
It is defined as amount of heat energy produced when unit mass of fuel is burned1cal=4.184 joule
S.KALAIYARASAN
- Apr 21st, 2009
The calorific value of the petrol is 48,000kJ/kg.The highest calorific value fuel is hydrogen is 141,790 kJ/kg.
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Stress Concentration
What is Stress Concentration? Give numerical examples.
harsh.ankalkoti
- Aug 21st, 2009
It is the concentration of stress at a particular point or region such as holes, sharp edges, corners etc., This is due to the reduced cross section area.As we know stress= force / area........The ...
vrsaikumar
- Jun 25th, 2009
Stress concentration or the stress will be maximum at the joints such as T joints and L joints. This results in fracture of materials easily. This is the reason whenever a material is manufactured w...
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Pump Displacement
Explain What is positive and non-positive displacement?
vrsaikumar
- Jul 9th, 2009
Positive displacement pumps are those which prevents undesirable flow and pumps the fluid within the closed space. Ex: Reciprocating pumps, Rotary pumps. Its efficiency is more when compared to non-p...
sachinlshinde123
- Jul 3rd, 2009
Positive displacement pump are those which discharge specific amount & quantity is constant?non positive pumps are those which discharge random amount & quantity varies.
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Thermal Efficiency
Why the thermal efficiency of the engine decreases at part load?
kanthasami
- Jul 26th, 2009
There are always some mechanical losses in the engine while running. These losses are more or less same at all the speeds. When the speed decreases, the output will obviously decreases. But, the losses remain same. So, the overall efficiency also decrease.
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Disc Brake
Why do most of the vehicle have disc brake only in the front axle?
NSK7777
- Jul 26th, 2009
While applying brake, the momentum of the vehicle will be transferred to front portion so it is necessary to have more braking force on front axle, that is why disc brake is used in front axle.
Gambit
- Jul 19th, 2009
Most of the vehicles are front wheel drives which uses disc brake in the front axles. This is because the inertia of the vehicle towards the front is more. So, to control the speed it is necessary to ...
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Railway Engine Motor
What motor do they use in railway engines for traction?
hemalshah94
- Aug 27th, 2010
In Local memu train, series motor is used bec?it? requires high torque?initially?e.g. Anand Memu, Vadodara memuIn Express train, I.M motor or Shunt motor is used bec. it requires high torque as well as constant speed e.g Ashram Express
bhargavmech
- Jul 28th, 2009
Traction motors used to drive trains are series motors that provide the required torque and horsepower to get massive amounts of weight moving
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Bike Gear
While riding bike in 5th gear at speed around 70-80 km/hr. suppose by any means the speed decreases such as break, but keeping the gear on 5th. Engine of the bike stops. Why? Explain.
theleo
- Sep 4th, 2009
Generally in 1st and 2nd gear bike gives huge torque and less speed. But as we increase gears engine gives speed to maintain or increase speed which already bike have and give less torque. so, whe...
vivekzgoal
- Sep 2nd, 2009
Because the engine will not produce a required torque in 5th gear, so power is transmitted from wheel to engine through clutch and gear box and finally it stops the engine.
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Archimedes' Principle
According to Archimedes principle, mass of an object in water would be less than mass of an object in air.So imagine an object of 5 kg and weight of a vessel containing water as 100 kg. The total weight is 105 kg. Now place a weighing machine under the water vessel and immerse the object into the water. Now can I except the weighing machine shows the weight less than 105 kg?
sudeeb
- Dec 20th, 2010
Acc to A.P -- Weight of the water displaced is equal to the weight of the body. So the weighing scale indicate the same weight 105 kg. ?but when we lift the body we will feel low weight due to the upward?bouncy?force. and body float/sink depend upon the bouncy force and metacentre.?
prashanthsekar
- Feb 19th, 2010
Firstly the question Cannot be directly related to Archimedes Principle, As the principle states that when an Body is immersed in water, The amount of water displaced by the body is equal to the weigh...
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Rotating Objects
Why do objects rotating with more speed appearing to be stationary and sometimes appearing as rotating in the opposite direction?
bhargavmech
- Aug 11th, 2009
The wagon-wheel effect (alternatively, or stagecoach-wheel effect, stroboscopic effect) is an optical illusion in which a spoked wheel appears to rotate differently from its true rotation. The wheel c...
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Turbine Efficiency
Will Bleeding of steam increases or decreases the efficiency of Turbine? Explain.
daruljothi
- Mar 12th, 2010
Bleed steam will increses the cycle efficiency of the unit because:1. It was takenout after considerable work output by HP turbine and 2. It can be used fully for heating of feed water and etc., incre...
technowiz
- Nov 1st, 2009
Bleed steam will increase the turbine efficiency this process is basicaly known as regeneration.
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Vanadium in HSS
What is the use of Vanadium in High Speed Steels?
mailmisterk
- Dec 26th, 2009
Vanadium in hss forms very hard carbides and thus increases the hardness and increases the wear resistance
Manjiri ayade
- Oct 13th, 2009
Vanadium is corrosion resistant. HSS is basically used to manufacture cutting tool or machining tool which operate at faster rate. So this property of Vanadium is essential here.
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Car Parked in Sloped Area
Why vehicle does not move when its gear is applied though parked in slope area?
shefeerps
- Jan 22nd, 2010
In Geared Position the vehichle is connected to the piston. The gravity force on car parked in a slope is not enough to move the piston systems in the multi cylinder engines to expand or compress inside the cylinder.
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Thrust Collar
The thrust collar provided at steam end of steam turbine rotor why we not provide it at exhaust end.
Tarik
- Feb 16th, 2016
There is higher pressure at steam end so it will push the thrust collar in oppsite of exhaust end, rotor axial force is towards exhaust end because of pressure diffrence so thrust collar will balance the axial movement by steam pressure.
franksma
- Nov 18th, 2010
It is not compulsary that the thriust collor should be in Steam inlet end,The thrust collor locations can be set on exhuast side also, it is all purely depends on the design of the steam turbine and the driven unit.
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VVTi
What VVTi written on new cars of Toyota stands for?
Chandimal
- Jan 8th, 2010
VVTi stands for Variable Valve Timing with Intelligence. Its a system which?improves?performance and efficiency of the engine. Mostly fitted with Toyota's.
sharu46
- Dec 30th, 2009
VVTi : Variable Valve Timing with Inteligence. It is the advanced version of the VVT engine. It changes the cam shaft position by using oil pressure. It is simmilar to CVVT in Hyundai.
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Gear Ratio
How gear ratio helps in power variation?
Nagesh M
- Jan 23rd, 2010
T1/T2=N2/N1, where T1 is no of teeth on driver; T2 is no of teeth on driven; N2 is speed of the driven gear & N1 is speed of the driver gear. The speed is inversly proportional to the torque developed by change of gears.
shefeerps
- Jan 22nd, 2010
N1/N2 = V1/V2where, N1=no. of teeth in 1st gearN2=no. of teeth in 2nd gearV1=velocity of 1st gearV2=velocity of 2nd gearVelocity varies with change in diameter of a rotating body system. Hence power.
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Strenth of Material
A cantilever beam is loaded a point on its ends what will be the effect in shear force?
debesh220
- Mar 19th, 2010
Due to the shear force the bar shows a hogging type bending moment. The shear force diagram is like a triangle triangle in +ve direction.
d_tyro_22
- Jan 27th, 2010
Considering that the load is a concentrated vertical point-load, acting on the free end of the cantilever, reaction at the rigid end can be calculated, shear-force diagram and bending moment diagrams ...
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Bearing Size
How to find the beraing number or bearing size?
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Water Energy
Water contains H2O, the hydrogen and oxygen present in the water can be used as fuel for the ic engine is it possible? then why it is not implemented nowadays.
Nimmala Goud
- May 25th, 2011
HI one n all.the project value for increasing efficiency of an engine using water as substitute of fuel is not the factor of revealing this technology, beside that's wonderful project n eco-friendly t...
halleybryanv
- Jan 5th, 2011
The equipment use for extracting hydrogen from water is too expensive this time. It is not economical to use it nowadays.
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Heat Direction
What is the direction of heat (i.e,whether it moves in straight line path or in wave motion or has dual nature)
Bhushan Kulkarni
- Aug 10th, 2011
As per heat transfer, heat flows in the direction perpendicular to area of heat flow.
VELMURUGAN
- Jul 13th, 2011
In wave form
Mechanical Engineering Interview Questions
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