Mechanical Engg. Set 4 (GATE) 2014

Description: 2014 (Set-1)
Number of Questions: 41
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Tags: 2014 (Set-1) Mechanical Engineering - ME
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Choose the most appropriate word from the options given below to complete the following sentence.

Many ancient cultures attributed disease to supernatural causes. However, modern science has largely helped ______ such notions.

  1. impel

  2. dispel

  3. propel

  4. repel


Correct Option: B
Explanation:

Correct option is (2).

Read the statements:

All women are entrepreneurs. Some women are doctors.

Which of the following conclusions can be logically inferred from the above statements?

  1. All women are doctors.

  2. All doctors are entrepreneurs.

  3. All entrepreneurs are women.

  4. Some entrepreneurs are doctors.


Correct Option: D
Explanation:

W = Women D = Doctors E = Entrepreneurs Venn-diagram

So it is clear from the venn-diagram that some entrepreneurs are doctors.

Choose the most appropriate phrase from the options given below to complete the following sentence.

The aircraft ______ take of as soon as its flight plan was filed.

  1. is allowed to

  2. will be allowed to

  3. was allowed to

  4. has been allowed to


Correct Option: C
Explanation:

It is a passive sentence and second part of sentence shows past activity so in first part we should also use past tense.

Find the odd one from the following group:

W, E, K, O
I, Q, W, A F, N, T, X N, V, B, D

  1. W, E, K, O

  2. I, Q, W, A

  3. F, N, T, X

  4. N, V, B, D


Correct Option: D
Explanation:

Correct option is (4).

For submitting tax returns, all resident males with annual income below Rs. 10 lakh should fill up Form P and all resident females with income below Rs. 8 lakh should fill up Form Q. All people with incomes above Rs. 10 lakh should fill up Form R, except non residents with income above Rs. 15 lakhs, who should fill up Form S. All others should fill Form T. An example of a person who should fill For T is

  1. a resident make with annual income Rs. 9 lakh

  2. a resident female with annual income Rs. 9 lakh

  3. a non-resident male with annual income Rs. 16 lakh

  4. a non-resident female with annual income Rs. 16 lakh


Correct Option: B
Explanation:

Correct option is (2)

The exports and imports (in crores of Rs.) of a country from 2000 to 2007 are given in the following bar chart. If the trade deficit is defined as excess of imports over exports, in which year is the trade deficit 1/5th of the exports?

  1. 2005

  2. 2004

  3. 2007

  4. 2006


Correct Option: D
Explanation:

Correct option is (4).

You are given three coins: one has heads on both faces, the second has tails on both faces, and the third has a head on one face and a tail on the other. You choose a coin at random and toss it, and it comes up heads. The probability that the other face is tails is

  1. 1/4

  2. 1/3

  3. 1/2

  4. 2/3


Correct Option: B
Explanation:

Correct option is (2).

$Lt_{x\rightarrow0}\frac{x-sinx}{1-cosx}$

is

  1. 0

  2. 1

  3. 3

  4. not defined


Correct Option: A
Explanation:

Given that the determinant of the matrix $\begin{bmatrix} \ 1 & 3 & 0 \ \ 2 & 6 & 4 \ \ -1 & 0 & 2 \ \end{bmatrix}$ is - 12, the determinant of the matrix $\begin{bmatrix} \ 2 & 6 & 0 \ \ 4 & 12 & 8 \ \ -2 & 0 & 4 \ \end{bmatrix}$ is

    • 96
    • 24
  1. 24

  2. 96


Correct Option: A
Explanation:

The matrix form of the linear system $\frac{dx}{dt}=3x-5y\hspace{0.2cm} and\frac {dy}{dt}=4x+8y$ is

  1. $\frac{d}{dt}\bigg(\begin{matrix} \ x \ \ y \ \end{matrix}\bigg) = \begin{bmatrix} \ 3 & -5 \ \ 4 & 8 \ \end{bmatrix}\bigg(\begin{matrix} \ x \ \ y \ \end{matrix}\bigg)$

  2. $\frac{d}{dt}\bigg(\begin{matrix} \ x \ \ y \ \end{matrix}\bigg) = \begin{bmatrix} \ 3 & 8 \ \ 4 & -5 \ \end{bmatrix}\bigg(\begin{matrix} \ x \ \ y \ \end{matrix}\bigg)$

  3. $\frac{d}{dt}\bigg(\begin{matrix} \ x \ \ y \ \end{matrix}\bigg) = \begin{bmatrix} \ 4 & -5 \ \ 3 & 8 \ \end{bmatrix}\bigg(\begin{matrix} \ x \ \ y \ \end{matrix}\bigg)$

  4. $\frac{d}{dt}\bigg(\begin{matrix} \ x \ \ y \ \end{matrix}\bigg) = \begin{bmatrix} \ 4 & 8 \ \ 3 & -5 \ \end{bmatrix}\bigg(\begin{matrix} \ x \ \ y \ \end{matrix}\bigg)$


Correct Option: A
Explanation:

Which one of the following describes the relationship among the three vectors, $\hat{i}+\hat{j}+\hat{k},2\hat{i}+3\hat{j}+\hat{k}\hspace{0.2cm}and\hspace{0.2cm} 5\hat{i}+6\hat{j}+4\hat{k}$?

  1. The vectors are mutually perpendicular.

  2. The vectors are linearly dependent.

  3. The vectors are linearly independent.

  4. The vectors are unit vectors.


Correct Option: B
Explanation:

The statistics of runs scored in a series by four batsmen are provided in the following table. Who is the most consistent batsman of these four?

   
Batsman Average Standard deviation
K 31.2 5.21
L 46.0 6.35
M 54.4 6.22
N 17.9 5.90
  1. K

  2. L

  3. M

  4. N


Correct Option: A
Explanation:

Consistency means minimum deviation so ‘K’ is the most consistent batsman. Average is used, when we want to select the best batsman in the manner of run scoring.

Critical damping is the

  1. largest amount of damping for which no oscillation occurs in free vibration

  2. smallest amount of damping for which no oscillation occurs in free vibration

  3. largest amount of damping for which the motion is simple harmonic in free vibration

  4. smallest amount of damping for which the motion is simple harmonic in free vibration


Correct Option: B
Explanation:

Critical damping is defined as the smallest amount of damping for which no oscillation occurs in free vibration.

The argument of the complex number $\frac{1+i}{1-i}$, where i = $\sqrt{-1}$, is

  1. $\pi$

  2. $-\frac{\pi}{2}$

  3. $\frac{\pi}{2}$

  4. $\pi$


Correct Option: C
Explanation:

A circular object of radius r rolls without slipping on a horizontal level floor with the centre having velocity V. The velocity at the point of contact between the object and the floor is

  1. zero

  2. V in the direction of motion

  3. V opposite to the direction of motion

  4. V vertically upward from the floor


Correct Option: A
Explanation:

For the given statements:

I. Mating spur gear teeth is an example of higher pair II. A revolute joint is an example of lower pair

Indicate the correct answer.

  1. Both I and II are false

  2. I is true and II is false

  3. I is false and II is true

  4. Both I and II are true


Correct Option: A
Explanation:

Higher pair has line or point contact and lower pair has surface contact. In spur gear there is line contact so it is a higher pair while in revolute joint there is surface contact so it is a lower pair.

A rigid link PQ is 2 m long and oriented at 20o to the horizontal as shown in the figure. The magnitude and direction of velocity VQ, and the direction of velocity VP are given. The magnitude of VP (in m/s) at this instant is

  1. 2.14

  2. 1.89

  3. 1.21

  4. 0.96


Correct Option: C
Explanation:

Correct option is (3).

Biot number signifies the ratio of

  1. convective resistance in the fluid to conductive resistance in the solid

  2. conductive resistance in the solid to convective resistance in the fluid

  3. inertia force to viscous force in the fluid

  4. buoyancy force to viscous force in the fluid


Correct Option: B
Explanation:

The maximum theoretical work obtainable, when a system interacts to equilibrium with a reference environment, is called

  1. Entropy

  2. Enthalpy

  3. Exergy

  4. Rothalpy


Correct Option: C
Explanation:

Entropy: Degree of randomness in the system. Enthalpy (H ) = U + PV U = Internal energy PV = Displacement work So enthalpy is the sum of internal energy and displacement work. Exergy or Available Energy: The maximum portion of energy which could be converted into useful work by ideal process and it reduces the system to dead state. Dead state: It is a state in equilibrium with the earth and its atmosphere.

For a completely submerged body with centre of gravity ‘G’ and centre of buoyancy ‘B’, the condition of stability will be

  1. G is located below B

  2. G is located above B

  3. G and B are coincident

  4. independent of the locations of G and B


Correct Option: B
Explanation:

y immersed body be in equilibrium the centre of gravity ‘G’ should be lower than the centre of buoyancy ‘B’.

Which one of the following is a CFC refrigerant?

  1. R744

  2. R290

  3. R502

  4. R718


Correct Option: C
Explanation:

In a power plant, water (density = 1000 kg/m3) is pumped from 80 kPa to 3 MPa. The pump has an isentropic efficiency of 0.85. Assuming that the temperature of the water remains the same, the specific work (in kJ/kg) supplied to the pump is

  1. 0.34

  2. 2.48

  3. 2.92

  4. 3.43


Correct Option: D
Explanation:

The jobs arrive at a facility, for service, in a random manner. The probability distribution of number of arrivals of jobs in a fixed time interval is

  1. Normal

  2. Poisson

  3. Erlang

  4. Beta


Correct Option: B
Explanation:

When jobs are coming in random manner then number of arrivals of jobs in a fixed time interval will follow poisson probability distribution. Service time will follow exponential distribution.

Which one of the following instruments is widely used to check and calibrate geometric features of machine tools during their assembly?

  1. Ultrasonic probe

  2. Coordinate Measuring Machine (CMM)

  3. Laser interferometer

  4. Vernier calipers


Correct Option: C
Explanation:

To check and calibrate geometric features of machine tools, we use laser interferometer.

The major difficulty during welding of aluminium is due to its

  1. high tendency of oxidation

  2. high thermal conductivity

  3. low melting point

  4. low density


Correct Option: A
Explanation:

Aluminium has high tendency of oxidation so during welding it is converted into aluminium oxide (Al2O3) and Al2O3 has very high melting point (2702oC) so now it will not melt and welding can not be performed easily.

The process of reheating the martensitic steel to reduce its brittleness without any significant loss in its hardness is

  1. normalising

  2. annealing

  3. quenching

  4. tempering


Correct Option: A
Explanation:

Correct option is (1).

For machining a rectangular island represented by coordinates P(0, 0), Q(100, 0), R(100, 50) and S(0, 50) on a casting using CNC milling machine, an end mill with a diameter of 16 mm is used. The trajectory of the cutter centre to machine the island PQRS is

  1. (- 8, - 8), (108, - 8), (108, 58), (- 8, 58), (- 8, - 8)

  2. (8, 8), (94, 8), (94, 44), (8, 44), (8, 8)

  3. (- 8, 8), (94, 8), (94, 44), (8, 44), (- 8, 8)

  4. (0, 0), (100, 0), (100, 50), (50, 0), (0, 0)


Correct Option: A
Explanation:

Correct option is (1).

A circular rod of length ‘L’ and area of cross-section ‘A’ has a modulus of elasticity ‘E’ and coefficient of thermal expansion ‘$\alpha$’. One end of the rod is fixed and other end is free. If the temperature of the rod is increased by $\triangle$T, then

  1. stress developed in the rod is E$\alpha$ $\triangle$T and strain developed in the rod is $\alpha$ $\triangle$T

  2. both stress and strain developed in the rod are zero

  3. stress developed in the rod is zero and strain developed in the rod is $\alpha$$\triangle$T

  4. stress developed in the rod is E$\alpha$ $\triangle$T and strain developed in the rod is zero


Correct Option: D
Explanation:

Consider a two-dimensional laminar flow over a long cylinder as shown in the figure below.

The free stream velocity is $U\omega$ and the free stream temperature $T\omega$ is lower than the cylinder surface temperature Ts. The local heat transfer coefficient is minimum at point

  1. 1

  2. 2

  3. 3

  4. 4


Correct Option: A
Explanation:

In laminar flow, the heat transfer coefficient is minimum where the thickness of boundry layer is maximum. The heat transfer coefficient is maximum where the thickness is minimum. For turbulent-region thickness of boundry layer is maximum at 3. For laminar region thickness of boundry layer is maximum at 2 so it will have minimum local heat transfer coefficient.

The main cutting force acting on a tool during the turning (orthogonal cutting) operation of a metal is 400 N. The turning was performed using 2 mm depth of cut and 0.1 mm/rev feed rate. The specific cutting pressure (in N/mm2) is

  1. 1000

  2. 2000

  3. 3000

  4. 4000


Correct Option: B
Explanation:

In solid-state welding, the contamination layers between the surfaces to be welded are removed by

  1. alcohol

  2. plastic deformation

  3. water jet

  4. sand blasting


Correct Option: B
Explanation:

Plastic deformation is used to remove contamination layers between the surfaces to be welded, in solid-state welding.

The integral $\oint\limits_x(ydx-xdy)$ is evaluated along the circle x2 + y2 = $\frac{1}{4}$ traversed in counter clockwise direction. The integral is equal to

  1. 0

  2. $-\frac{\pi}{4}$

  3. $-\frac{\pi}{2}$

  4. $\frac{\pi}{4}$


Correct Option: C
Explanation:

In the following table, x is a discrete random variable and p(x) is the probability density. The standard deviation of x is

     
x 1 2 3
p(x) 0.3 0.6 0.1
  1. 0.18

  2. 0.36

  3. 0.54

  4. 0.6


Correct Option: D
Explanation:

A block R of mass 100 kg is placed on a block S of mass 150 kg as shown in the figure. Block R is tied to the wall by a massless and inextensible string PQ. If the coefficient of static friction for all surfaces is 0.4, the minimum force F (in kN) needed to move the block S is

  1. 0.69

  2. 0.88

  3. 0.98

  4. 1.37


Correct Option: D
Explanation:

A rigid uniform rod AB of length L and mass m is hinged at C such that AC = L/3, CB = 2L/3. Ends A and B are supported by springs of spring constant k. The natural frequency of the system is given by

  1. $\sqrt\frac{k}{2m}$

  2. $\sqrt\frac{k}{m}$

  3. $\sqrt\frac{2k}{m}$

  4. $\sqrt\frac{5k}{m}$


Correct Option: D
Explanation:

A reversible heat engine receives 2 kJ of heat from a reservoir at 1000 K and a certain amount of heat from a reservoir at 800 K. It rejects 1 kJ of heat to a reservoir at 400 K. The net work output (in kJ) of the cycle is

  1. 0.8

  2. 1.0

  3. 1.4

  4. 2.0


Correct Option: C
Explanation:

In exponential smoothening method, which one of the following is true?

  1. 0 $\leq$ $\alpha$ $\leq$ 1 and high value of $\alpha$ is used for stable demand

  2. 0 $\leq$ $\alpha$ $\leq$ 1 and high value of $\alpha$ is used for unstable demand

  3. $\alpha$ $\geq$ 1 and high value of $\alpha$ is used for stable demand

  4. $\alpha$ $\leq$ 0 and high value of $\alpha$ is used for unstable demand


Correct Option: B
Explanation:

High value of ‘$\alpha$’ shows more weightage is given to immediate forecast. Less value of ‘$\alpha$’ shows less weightage is given to immediate forecast or almost equal weightage is given. So high value of ‘$\alpha$’ is chosen when nature of demand is not reliable or unstable.

Jobs arrive at a facility at an average rate of 5 in an 8 hour shift. The arrival of the jobs follows Poisson distribution. The average service time of a job on the facility is 40 minutes. The service time follows exponential distribution. Idle time (in hours) at the facility per shift will be

  1. $\frac{5}{7}$

  2. $\frac{14}{3}$

  3. $\frac{7}{5}$

  4. $\frac{10}{3}$


Correct Option: B
Explanation:

The non-dimensional fluid temperature profile near the surface of a convectively cooled flat plate is given by $\frac{T_w-T}{T_w-T_w}$ = $a+b\frac{y}{L}+c\bigg(\frac{y}{L}\bigg)^2$, where y is measured perpendicular to the plate, L is the plate length, and a, b and c are arbitrary constants. TW and $T_\omega$ are wall and ambient temperatures, respectively. If the thermal conductivity of the fluid is k and the wall heat flux is q², the Nusselt number $Nu=\frac{q''}{T_w-T_\infty}\frac{L}{K}$ is equal to

  1. a

  2. b

  3. 2c

  4. (b + 2c)


Correct Option: B
Explanation:

For the given assembly: 25 H7/g8, match Group A with Group B:

     
Group A Group B
P. H I. Shaft type
Q. ITS II. Hole type
R. IT7 III. Hole tolerance grade
S. g IV. Shaft tolerance grade
  1. P - I, Q - III, R - IV, S - II

  2. P - I, Q - IV, R - III, S - II

  3. P - II, Q - III, R - IV, S - I

  4. P - II, Q - IV, R - III, S - I


Correct Option: D
Explanation:

H $\rightarrow$ Hole type g $\rightarrow$ Shaft type H7 $\rightarrow$ A hole and 7 indicates its tolerance grade g8 $\rightarrow$ A shaft and 8 indicates its tolerance grade

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