HPCL Mechanical Engineer Mock Test - 5 - Mechanical Engineering MCQ

Desolate: Empty And with out person, making you feel sad/frightened
absolute: Total and complete
Obsolete: Something no longer in use
Primitive: Belonging to an early stage in the development of humans and animals

Use structure “subject + auxiliary + past participle ”
As per the given above sentence is given in Passive Voice.
You have been warned.
Therefore , required answer will be option A .

Unconnected not joined together or to something else.
Chaotic : in a state of complete confusion and disorder.
Unaccountable : unable to be explained; Inexplicable.
Confusing : bewildering or perplexing.
Inexplicable : unable to be explained or accounted for.

Synonym of Inexplicable is Unaccountable

To lynch is to murder, or unlawfully kill. When an angry mob kills someone they believe is guilty of a crime, they lynch that person. Through history, when a group of people murders someone, especially by hanging him by the neck, they are usually said to lynch him.

( x=0.222)-eq1
(10x=2.22 after multiplying 10 to both side)-eq2
(9x=2after subtract eq2 from 1)
x= 2/9
we have find 9x so,
9×(2/9)
9×2/9
2

63 is divisible by 7 for any power, so required remainder will depend on the power of 4
Required remainder 

find remainder when 99/4 ( by 4 because to check periodicity)

Let the widh = 2x
Length = 3x
2x × 3x = 54
x = 3 cm
Hence, Option A is correct.

Hence, Option A is correct.

The number of students who play both the games = (30 + 50 + 40)% – 100% = 20%
Hence, Option D is correct.

Hence, Option D is correct.

AB || CD and t transversal intersects them at E and F
∠BEF + ∠EFD = 180° (co-interior angles)

⇒ ∠FEG + ∠EFG = 90°
In Δ GEF
∠EGF + ∠FEG + ∠EFG = 180°
∴ ∠EGF + 90° = 180°
∴ ∠EGF = 90°.
The above result can be restated as :
If two parallel lines are cut by a traversal, then the bisectors of the interior angles on the same side of the traversal intersect each other at right angles.

So the answer = (100 – 50)% of 700 + (100 – 60)% of 500 = 550
Hence, Option D is correct.

We know that 
By applying that rule here, we get 
since 

Weights → A + B + C + D = 64 × 4 = 256 kg
Weights → A + B = 50 × 2 = 100 kg
Weights → B + C + D = 70 × 3 = 210 kg
Weights → A + B + B + C + D = 100 + 210 = 310 kg
So the answer = 310 – 256 = 54 kg
Hence, Option D is correct.

Paper will be folded from up to down then right to left.

Concept:

E = Young's Modulus of elasticity = Stress / strain

G = Shear Modulus or Modulus of rigidity = Shear stress / Shear strain

ν = Poisson’s ratio = - lateral strain / longitudinal strain

K = Bulk Modulus of elasticity = Volumetric stress / Volumetric strain

Relation between E, K and ν

E = 2G (1 + ν)

E = 3K (1 - 2ν)

Calculation:

E = 3K (1 - 2ν)

The pressure angle, representing the steepness of the cam profile, is the angle between the normal to the pitch curve at a point and the direction of the follower motion. It varies in magnitude at all instants of the follower motion. A high value of the maximum pressure angle is not desired as it might jam the follower in the bearings.

P_n = The component of force P, normal to section FG = P cos θ

P_t = The component of force P, along the surface of the section FG (tangential to the surface FG) = P sin θ

σ_n = Normal Stress across the section FG

σ_n=σcos²θ

σ_t = Tangential/Shear Stress across the section FG

In a free vortex flow, total mechanical energy remains constant. There is neither any energy interaction between an outside source and the flow nor is there any dissipation of mechanical energy within the flow. The fluid rotates by virtue of some rotation previously imparted to it or because of some internal action.

Some examples are a whirlpool in a river, the rotatory flow that often arises in a shallow vessel when liquid flows out through a hole in the bottom (when water flows out from a bathtub or a washbasin), and flow in a centrifugal pump case just outside the impeller.

Crystal structure of Material

FCC: - Ni, Cu, Ag, Pt, Au, Pb, Al, Austenite or Ƴ-iron

BCC: - V, Mo, Ta, W, Ferrite or α-iron, δ-ferrite or δ-iron

HCP: - Mg, Zn

Cobalt: - HCP < 420°C, FCC > 420°C

Chromium: - HCP < 20°C, BCC > 20°C

Glass: - Amorphous

Normalizing: Heat the steel from 30°C to 50°C above its upper critical temp, held about fifteen minutes, and then allowed to cool down in still air. The homogeneous structure provides a higher yield point, ultimate tensile strength, and impact strength with lower ductility to steels.

Main objective

1. Refine grain size in metal, improve strength and hardness, reduce ductility

2. Remove cold worked stress.

3. Remove dislocations due to hot working.

An isentropic process is also known as a reversible adiabatic process.

If the process is reversible and adiabatic: dQ_rev = 0 ⇒ dS = 0

Entropy analysis for a closed system:

Case 1: For an internally reversible process (δs)_gen = 0

When heat is added to the system ⇒ (δQ) = +ve ⇒ ds = +ve

When heat is rejected from the system ⇒ (δQ) = -ve ⇒ ds = -ve

For adiabatic process ⇒ (δQ) = 0 ⇒ ds = 0 (ISENTROPIC)

Case 2: For internally irreversible process (δs)gen ≠ 0 ⇒ (δs)gen = +ve

When heat is added to the system ⇒ (δQ) = +ve ⇒ ds = +ve

When heat is rejected from the system ⇒ (δQ) = -ve ⇒ ds = -ve or +ve or zero

​Since (δs)_gen = +ve and (δQ) = -ve so change in entropy, ds can be zero is (δQ/T) = δs)gen. In this case, the process will be ISENTROPIC

For adiabatic process ⇒ (δQ) = 0 ⇒ ds = +ve

Thus for a process to be isentropic, there are two cases:

Reversible adiabatic process

The irreversible process where (δQ/T) = δs)gen

Note: Irreversible adiabatic process is not an isentropic process.

Change in length of the bar:

δL = PL/AE

The ratio between the force and deflection is referred to as the spring rate or stiffness of the beam or coil.

Equivalent spring constant:

k = F/x = P/δL = AE/L

Stress = force per unit area, i.e. F / A or N/m²

Strain = change in length per unit original length, i.e. m/m or mm/mm.

Hooke’s Law holds good up to the proportional limit.

According to Hooke’s Law, stress is directly proportional to strain within the elastic limit.

Note: Stress is not pressure per unit area because pressure itself is force per unit area.

v=μ/ρ

⇒ μ for air increases with the rise in temperature, and ρ decreases with the rise in temperature, so kinematic viscosity increases.

α=K/ρC_p

⇒ For air, K increases with the rise in temperature, and ρ decreases with the rise in temperature. So the value of thermal diffusivity increases.

So out of given values, the value of specific gravity does not change increase with the temperature.

In Brittle materials under tension test undergoes brittle fracture i.e. their failure plane is 90° to the axis of load, and there is no elongation in the rod that’s why the diameter remains the same before and after the load. Example: Cast Iron, concrete, etc.

But in the case of ductile materials, material first elongates and then fails, their failure plane is 45° to the axis of the load. After failure, cup-cone failure is seen. Example Mild steel, high tensile steel, etc.