RCFL MT Mechanical Mock Test - 9 - Mechanical Engineering MCQ

C.O.P decreases as work input increases. C.O.P =

The unit of dynamic viscosity is kg/(m.sec), and the dimension is ML^-1T-1

C_d = C_c × C_v

Where,

C_c = Coefficient of contraction

C_v = Coefficient of velocity

Gravity does cause things to fall with increasing speed, but as they speed up, the viscous force due to air increases. Eventually, the viscous force due to air is enough to balance the force of gravity, so the acceleration stops, and the raindrop reaches a constant terminal velocity.

Conservation of linear momentum:

m₁u₁ + m₂u₂ = (m₁ + m₂) V

m(2u) + m(-u) = (2m) V

mu = 2mV

V = u/2

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.

Correct Answer :- a

Explanation : For 450 m head of water, Pelton wheel shall be used.

A Pelton turbine or Pelton wheel is a type of hydro turbine (specifically an impulse turbine) used frequently in hydroelectric plants. These turbines are generally used for sites with heads greater than 300 meters.

The water in a Pelton turbine is moving quickly and the turbine extracts energy from the water by slowing the water down, which makes this an impulse turbine.

Resilience is defined as the capacity of a strained body for doing work on the removal of the straining force.

Proof resilience is defined as the maximum strain energy stored in a body. So, it is the quantity of strain energy stored in a body when strained up to an elastic limit (ability to store or absorb energy without permanent deformation).

Modulus of resilience is defined as proof resilience per unit volume. It is the area under stress–strain curve up to the elastic limit.

In the Power screw, the torque Mt required to lower the load is given by

M_t = Wd_m/2 tan (ϕ−α) where, W = load on the screw in N, d_m = the mean diameter of the screw-in m,

ϕ = friction angle and α = helix angle

Case 1. when ϕ ≥ α

tan (ϕ - α ) ≥ 0, thus M_t ≥ 0.

i.e., positive torque is required to lower the load. Thus the load will not turn the screw and will not descend on its own unless an effort is applied.

Such cases of screws are known as 'Self-locking screws.’ And the screw will hold the hold without any application of the brake.

Also, as ϕ ≥ α

tan ϕ ≥ tan α

Case 2. when ϕ < />

tan (ϕ - α ) < 0,="" thus="" />_t < />

i.e., negative torque is required to lower the load. The load will turn down the screw and will descend on its own unless a restoring torque is required to hold the load.

Such cases of screws are known as 'overhauling of the screw' or back drawing of the screw.

• So it is evident from the graph that the strain is proportional to stress or elongation is proportional to the load giving a straight-line relationship. This law of proportionality is valid up to a point A. Point A is known as the limit of proportionality or the proportionality limit.
• For a short period beyond point A, the material may still be elastic in the sense that the deformations are completely recovered when the load is removed. The limiting point B is termed as Elastic Limit.
• Beyond the elastic limit, plastic deformation occurs, and strains are not totally recoverable. There will be thus permanent deformation or permanent set when the load is removed. These two points are termed upper and lower yield points, respectively. The stress at the yield point is called the yield strength.
• A further increase in the load will cause marked deformation in the whole volume of the metal. The maximum load which the specimen can withstand without failure is called the load at the ultimate strength. The highest point ‘E' of the diagram corresponds to the ultimate strength of a material.
• Beyond point E, the bar begins to form the neck. The load falls from the maximum until a fracture occurs at F.

One word substitution is Dotage.

Imbecility: Stupid or insane behaviour.

Youth: The period between childhood and adult age.

Dotage: The period of life in which a person is old and weak, especially with some loss of mental ability.

Superannuation: Regular payment made into a fund by an employee towards a future pension.

• Consequences are results of something that already had happened whereas conclusions are the final verdits of discussions or ideas.
• Results: something that happens because of something else; the final situation at the end of a series of actions
• Conclusions: an opinion that you reach after thinking about something carefully
• Difficulties: the state or condition of being difficult
• Applications: the action of putting something into operation.

Hence Correct Answer is Option A

Covert means not openly acknowledged or displayed

Synonyms: secret, furtive, clandestine, surreptitious, stealthy

We cannot win in Afghanistan while Pakistan gives covert support to the Taliban
The climax of the book, a covert operation in Iran, is flaccid and unconvincing
Legally, it will be a deniable covert action which will put the CIA in the lead

The given sentence is in the active voice: "I expect you to complete this work before sunset."

The correct transformation of this sentence into the passive voice is: "You are expected to complete this work before sunset."

Therefore, the correct answer is option B: "You are expected to complete this work before sunset."

Sum of 100 numbers =100×210=21000
Sum of 120 numbers =120×200=24000
Sum of 20 numbers =24000−21000=3000
∴ Average of 20 new numbers =3000/20=150

Hence, Option D is correct.

∠DAC = ∠B + ∠C
(Exterior angle prop. of a Δ ABC)
According to question,
130° = 2A + 3A
5A = 130°
A = 26°
∴ ∠B = 52°; ∠C = 78°

Area of Rectangle = Length * Breadth.
Area of Rhombus Using DiagonalsA = ½ × d₁ × d₂
Area of quadrilateral willl be calculated based on which type of quadriateral it is-
Area of trapezium willl be 1/2 (sum of Parallel sides )*height.

The number π  is a mathematical constant. Originally defined as the ratio of a circle's circumference to its diameter, it now has various equivalent definitions and appears in many formulas in all areas of mathematics and physics. It is approximately equal to 3.14159. It has been represented by the Greek letter "π" since the mid-18th century, though it is also sometimes spelled out as "pi". It is also called Archimedes' constant.

Hence, Option A is correct.

4√6*3√24=4√6*3√2*√2*√*2*√3

=4√6*6√6

4*6*√6*√6=4*6*6=24*6=144

Let the required number be x.
As given,

Daughter of grandmother = Aunt
Aunt’s only brother = Father

First and fouth letters are interchanged while second and third letters are interchanged.

From the common explanation, we get Sagar scored 2nd lowest marks.

Hence, Option D is correct.

References:

Tarun scored more marks than Priyam but less than Rahul.

Sagar neither scored 3rd highest nor scored lowest marks.

Priyam scored more marks than Anurag.

Sagar scored less than Tarun, who scored 87 marks.

Inferences:

From the above references, we get the following arrangements

Rahul > Tarun (87) > Priyam > Sagar > Anurag

Hari has no brother or sister.
So, he is his father’s only son, wife of Hari’s father’s son - Hari’s wife
Hari’s wife is the man’s mother.
Man is Hari’s son.

The sex ratio of Punjab is 895.

• The sex ratio in Punjab is 895 i.e. for every 1000 males which are below the national average of 940 according to the 2011 census.
• In 2001 the female sex ratio in Punjab was 876 per 1000 males.
• Punjab has a population of 2.77 Crores, an improvement from the figure of 2.44 Crore in 2001 census, according to data from Census 2011.
• Punjab's total population as per the 2011 census is 27,743,338 of which 14,639,465 and 13,103,873 are male and female respectively.
• Punjab's literacy rate has seen an upward trend and is 75.84% as per the census of the population in 2011.
• Of that, male literacy stands at 80.44% while female literacy stands at 70.73%.