1.) What is the direction of tangential acceleration ?
Ans:The direction of tangential acceleration may be same or opposite to that of angular velocity.

2.)Why excess air is required to burn a fuel completely ?
Ans: Excess air is required to ensure adequate mixing of fuel and air, avoid smoke, minimize slagging in coal burning, and to ensure maximum steam output.

3.)Which type of plant will you recommend for remote location if power is required in six to twelve months time ?
Ans: Diesel engine power plant.

4.)What do you understand by forced convection ?
Ans: When convection heat transfer occurs between a solid body and a fluid and where circulation of fluid is caused and controlled by some mechanical.

5.). What is Sentinel Relief Valve?
Ans. It’s a special type valve system. The valve will open when exhaust casing pressure is excessive (high). The valve warns the operator only; it is not intended to relieve the casing pressure.

6.)What is boundary layer thickness in turbulent boundary layer ?
Ans: In ease of turbulent boundary layer, boundary layer thickness is defined as the distance from solid surface at which the fluid velocity is 99% of the undisturbed free stream velocity.
Near the surface of solid, there is laminar flow which changes to buffer zone and finally turbulent region.

7.). Stirling cycle with regenerative arrangement and Carnot cycle operate within same temperature limits. What can be said about thermal efficiencies of these two ?
Ans: Thermal n of both will be same.

8.). What is the frequency of secondary imbalance in four-stroke engine ?
Ans: Two times the engine speed.

9.)What is the difference between Specification,Codes, Standards?
Ans. Specification is describing properties of any type of materials. Code is procedure of acceptance and rejection criteria. Standard is accepted values and compare other with it.

10.) What is difference between Welding and Brazing?

Ans. In Welding concentrated heat (high temperature) is applied at the joint of metal and fuse together. In Brazing involves significantly lower temperatures and does not entail the melting of base metals. Instead, a filler metal is melted and forced to flow into the joint through capillary action.

11.)What is the purpose of Scrapper Ring?

Ans. It scraps the excess lube oil from the cylinder walls. there by preventing oil from entering combustion zone.

12)What is DTSI Technology?

Ans. DTSI stands for Digital Twin Spark Plug Ignition. The vehicles with DTSI Technology use 2 spark plugs which are controlled by digital circuit. It results in efficient combustion of air fuel mixture.

--»Digital - Since the spark generation will be initiated by a microchip.
--»Twin - Since two spark plugs will be used.
--»Spark ignition - Since the ignition will be done via a spark.

13.)What is the difference between Sudden Force and Impact Force?

Ans. An impact is a high force or shock applied over a short time period when two or more bodies collide.

A force which applies on the body (material) suddenly is known as sudden force.

14).What is ATFT Technology used in Honda Hunk?
Ans.-ATFT means Advance Tumble Flow Induction Technology,
Tumble flow means swirling. In this technology fuel air mixture from the carburetor into the engine cylinder with a swirl action. The advantage being one gets a more efficient burning of fuel hence more power and better fuel economy with lesser emissions.

15).Why we do not use same technology to start both SI /CI engine
Ans.-The S.I. or spark ignition engine uses petrol as a fuel and the C.I. or compression ignition engine uses diesel as a fuel. Both the fuels has different compression ratio.
In SI engine the compression ratio is 8-12:1.
In CI engine the compression ratio is 16-22:1.
So in case of SI engine, the compression ratio is not sufficient for fuel to burn so a spark plug is used, whereas in ci engine, the compression ratio is so high that due to its internal heat the fuel is combusted so there is no need for a spark plug. so the technology used in si engine is different from CI engine.

16).What is a Newtonian fluid?
Ans.-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.

17.)Explain the reason that why big tyres are used in rear of vehicles.
Ans-Large tyres provide larger surface area touching the ground, thus providing the more pulling power. Basically tractors have larger rear tyres because tractors don’t have to operate at higher speeds, thus getting the same ground speed with larger tyres. Moreover gear ratios don’t have to be as high as b/c of the tyres.

18.)Explain the reason that why the tyres are always black in colour. Is this phenomena related to the heat conduction?
Ans-Tyres colour is black due to the proportion of carbon mixed in it during the vulcanization of the rubber, to make the tyre shear resistant. Without vulcanization tyres won't be able to bear the friction heat and stress of the road. Thus carbon is responsible for giving tyres the prominent black colour. Adding of carbon prevents tyres from rapidly deteriorating because when ozone combines with the ultraviolet light from the sun. It attacks the polymer of the tyre.

19.)During the drive torque, what will be the weight shift?
In case of cars the torque is applied to the rear wheels, thus limiting accelerator due to front wheel drive due to weight transfer. This drive is bolted to the chassis of the car. Modern manufacturers therefore design rear wheel drive to have similar handling to front wheel drive wherever possible via suspension tuning.


  1. Very useful for remember our mechanical knowledge it was quit good keep it up higher questions like DE'ALEMBERT'S PRINCIPLE, QUILLS THEOREM, TOGGLE MECHANISM, HYPERMESH GEARBOX PRINCIPLE ETC., questions i am also have some questions how to post our questions?

  2. thank fr d info...vry usful to us..once again thanx

  3. thanks for valuable Q&A .....its very use full for mechs

  4. Hey guys, I have a question.
    Why the of a train is not stopped each and every juction,normally we used to stop our vehicles (such as two r four wheelers even the aeroplane) during a time delay and we start again.

    So why the train engine is not stopped at its junction...?

    1. Bhai train ka engine start hone me 19-22 litre Diesel use hota h... And normally yadi vo junction pe 1 hour bhi on raha to... 5 litre Diesel h consume karata h...

  5. Thanks a lot sir for all these imp. Things