MECHANICAL ENGINEERING TOP MODEL PAPER.

01.The moment diagram for a centilever beam carrying uniformly distributed load will be

parabola.

Explanation:-

The bending moment diagram for a cantilever beam loaded with uniformly distributed load will be a parabolic curve. The maximum bending moment of a cantilever beam of length l and carrying a uniformly distributed load of w per unit length lies at the middle of its length.

02.The moment diagram for a cantilever beam carrying concentrated load at end of the beam will be

triangle.

03.The rollers of a cycle chain are subjected to following type of stress

fatigue.

Explanation:-

Material fatigue is a phenomenon where structures fail when subjected to a cyclic load. 

04.Two sheets of same material but different thickness can be butt welded by

changing the size of one electrode.

Explanation:-

Butt welding is accomplished by heating up two pieces of metal, or applying pressure, or doing both of those.

05.In arc welding operations the current value is decide by

diameter of electrode.

Explanation:-
Commonly used electrode diameters are 2, 2.5, 3.18, 4, 5 and 6 mm. Length of electrodes may depend on diameter of core wire ranging from 250 to 450 mm i.e. larger the core diameter larger the length. However, special electrodes may be of 8-10 mm diameter.

06.Sands are graded according to their

clay content and grain size.

07.A long column fails by

buckling.

Explanation:-

Shorter and wider column normally fails under compression failure. When the axially loaded stress exceeds allowable stress, compression failure occurs.Failure due to crushing is basically material failure. Whereas failure due to buckling is geometric instability (which generally occurs in long or slender columns).

08.In planetary motion, following parameter remains constant

total angular momentum.

Explanation:-

How do Newton's laws explain planetary motion?

Newton's First Law of Motion states that a body in motion keeps the same motion unless acted upon by an outside force.The force of gravity causes the moving planets to travel in roughly circular orbits around the sun.

09.Francis, kaplan and propeller turbines fall under the category of

Reaction turbines.

Explanation:-

What is the difference between Kaplan and Francis turbine?

Efficiency of Kaplan turbine is higher than Francis turbine.In Kaplan turbine, the water flows axially in and axially out while in Francis turbine it is radially in and axially out. The runner blades in the Kaplan turbine are less in number as the blades are twisted and covers a larger circumference.

10.Reaction turbines are used for

high head and high discharge.

11.Which type of gears are used for shaft axes having an offset ?

Hypoid gears.

12.In a governor, if the equilibrium speed is constant for all radii of rotation of balls, the governor is said to be

isochronous.

13.The maximum efficiency of Pelton turbine is _________

50%.

Explanation:-
The optimum value of the overall efficiency of a Pelton turbine depends both on the values of the specific speed and the speed ratio.

14.For small discharge at high pressure following pump is preferred:

Reciprocating.

Explanation:-

Reciprocating pumps are used majorly In boiler water feeds as water needs to be feed at high pressure and we can't use centrifugal pumps due to cavitation problem.

15.For helical gears, the helix angle generally ranges from

0 to 30 degrees.

16.The differential gear in the automobiles is used to

Help in turning.

17.Cupola is best suited for melting

Ferrous metals.

18.In case of slotting machine, cutting action takes place in

downward stroke.

19.In which type of welding molten metal is poured for joining the metals ?

Thermit welding.

20.In a single V- butt welds, the angle between edges is kept about

70 to 90º.

21.A half nut is :

mechanism that locks the lathe carrige to the lead screw for thread cutting.

22.Automobile gears are generally manufactured by:

Hobbing.

23.The binder in case of synthetic sand used for moulding is :

Bentonite and water.

24.The critical temperature for water  

374º C.

25.The property by which an amount of energy is absorbed by a material without plastic deformation, is called:

Resilience.

26.Which one of the following is the condition for stable equilibrium for a floating body?

The metacenter is above the center of gravity.

27.In which type of welding a pool of molten metal is used

electro slag.

28.Hot tears are casting defects

Which occur due to discontinuity in metal casting resulting from hindered contraction.

29.Bevel gears are used to connect

Intersecting and coplanar shafts.

30.Contact ratio is defined as ratio of

Arc of contact/ circular pitch.

31.Which law of motion (of Newton) give the measure of force ?

Newton's second law.

32.The shear stress at the centre of a circular shaft under torsion is

zero.