BDL MT Mechanical Mock Test - 2 Free Online Test 2026

dV = 0.2%

Compressibility (β) =

Cementite: Cementite or Iron Carbide has the chemical formula Fe3C and contains 6.67% carbon by weight. It is the hardest structure that appears in the iron-carbon equilibrium diagram. Cementite has an orthorhombic crystal structure and is extremely hard and brittle as compared to austenite and ferrite.

Martensite: It is a metastable phase of steel formed by the transformation of austenite below 320°C. Martensite is an interstitial supersaturated solid carbon solution in α – Iron and has a body-centred tetragonal lattice. It has a carbon content of up to 2% and is extremely hard and brittle. It is a product of rapid cooling (quenching) and possesses an acicular or needle-like structure.

The hardness of steel depends upon the amount of cementite. Martensite was obtained after hardening treatment of steel.

Steels with low carbon content do not respond appreciably to hardening treatment because the main constituent is soft ferrite. If hypo-eutectoid steel is cooled rapidly, martensite is formed.

1) Mechanical equilibrium: When there are no unbalanced forces within the system and between the system and the surrounding, the system is said to be under mechanical equilibrium.

2) Chemical equilibrium: The system is said to be in chemical equilibrium when no chemical reactions are going on within the system. There is no transfer of matter from one part of the system to another due to diffusion.

3) Thermal equilibrium: When the system’s temperature is uniform and not changing throughout the system, and in the surroundings, the system is said to be in thermal equilibrium.

An adiabatic process is one in which no heat transfer takes place to or from the system during the process.

An isenthalpic process or iso-enthalpic process is a process that proceeds without any change in enthalpy, H; or specific enthalpy, h

An isentropic process is one in which entropy remains constant (Δs=0)

An isobaric process is a thermodynamic process in which the pressure stays constant: ΔP = 0

An isochoric system is one in which volume is held constant (ΔV=0). Isochoric processes can also be referred to as isometric or isovolumetric

An isothermal process is one in which there is no temperature change (ΔT=0)

A throttling process is a thermodynamic process in which the enthalpy of the gas or medium remains constant (h = const). In fact, the throttling process is one of the isenthalpic processes. On the other the throttling process cannot be isentropic; it is a fundamentally irreversible process.

Some familiar properties are pressure, temperature, volume, and mass.

Properties may be divided into two categories, i.e., extensive (dependent of mass) and intensive (independent of mass) properties.

As the hot coffee remains hot for a long time so neither heat nor mass is exchanged with the surroundings and hence it is an example of isolated system.

If two or more shaft of different material, diameter or basic forms are connected together in such a way that each carries the same torque, then the shafts are said to be connected in series.

Completely constrained motion is a type of constrained motion in which relative motion between the links of a kinematic pair occurs in a definite direction by itself, irrespective of the external forces applied.

Correct Answer :- D

Explanation : The process of preheating involves heating the area around the weld joint or the entire part to a specified temperature before welding. This reduces the cooling rate of the weld and drives out moisture, which in turn helps prevent hydrogen buildup and the potential for cracking.

A rotameter (variable area meter) is a flow meter that measures the volumetric flow of liquids and gases. There is no difference between a rotameter and a flow meter, and these terms are used interchangeably. The technique for measuring flow is accomplished by a freely moving float finding equilibrium in a tapered tube.

Counterboring: It is an operation of enlarging a drilled hole partially for a drilled hole.

Countersinking: It is an operation of forming a conical shape at the end of a drilled hole.

Trepanning: It is an operation of producing a hole by removing the metal along the circumference of a hollow cutting tool.

For a fully developed laminar viscous flow through a circular pipe, the maximum velocity is equal to twice the average velocity.

i.e. V_max=2×V_avg

V_avg=0.5×V_max

Point to be remembered:

For the fully developed laminar flow through the parallel plates, the maximum velocity is equal to the (3/2) times of the average velocity.

i.e.

Cutting tools may be classified according to the number of major cutting edges (points) involved as follows:

• Single point: e.g., turning tools, shaping, planning, and slotting tools (parting tool), and boring tools

• Double (two) point: e.g., drills

• Multipoint (more than two): e.g., milling cutters, broaching tools, hobs, gear shaping cutters, etc.

dU + PdV = dH which is enthalpy

Hence, the correct option is (C).

Conclusions:

I. All papers are gas → True.

II. Some gas is paper → True.

Hence, both conclusions I and II follow.

a friend of mine = 4916

mine lots of metal = 3109

a piece of metal = 7163

From eq (i) and (ii), of mine = 1, 9

From eq (ii) and (iii), of metal = 1, 3

So, of = 1 metal = 3, mine = 9. Similarly, you can find

the code of all by comparing equations.

a=6 lots= 0

piece = 7 friend = 4

a = 6, of = 1 and mine = 9- and we don't know the code ofpleasure but seeing the answer options 6, 1, 9, is available in answer option (3) only

Consecutive prime numbers are subtracted and added.

Hence, option P is the correct answer.

From statement I

From the statement, we cannot determine that A, B, C, and D are facing the centre because we clearly know that B is facing outside.

From statement II we cannot determine that A, B, C, and D face the centre because we clearly show that D is facing Outside.

From statement III

From statement III, we clearly say that A, B, C, and D are facing the centre.

(6*5) + (4*2) = 38

Similarly,

(7*6) + (1*8) = 50

= Product of (0.003 x 25 + 4.65) and (0.05 x 24 - 0.2)

= 4.725 x 1

= 4.725

Option (2):

= Sum of (23 x 0.005 + 4 x 0.003) and 3.598

= 0.127 + 3.598

= 3.725

Option (4):

= 2 x 3 x 5.6 x 0.005 + 45.57 x 0.1

= 4.725

Hence, option (2) is odd among all four options.

The correct answer is option 3. There is no such word as ''deecree.'' This spelling is wrong. The correct word is ''decree'' which means ''an official order that has the force of law.''
Precise: marked by exactness and accuracy of expression or detail.
Decrepit:  worn out or ruined because of age or neglect.
Vanquish: defeat thoroughly.

The sentence has no grammatical errors.
Therefore, the correct answer is option 4.

The past tense form of the verb 'to cast' is cast and not casted. Therefore, the correct answer is option 1.
Improved sentence - The statue was cast in pure gold and was studded with diamonds.
The forms of cast is 
cast  cast  cast 
like Put Put Put