Mechanical Engg. Set 3 (GATE) 2014

Description: 2014 (Set- 3)
Number of Questions: 38
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Tags: 2014 (Set- 3) Mechanical Engineering - ME
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The value of one U.S. dollar is 65 Indian Rupees today, compared to 60 last year. The Indian Rupee has _________.

  1. depressed

  2. depreciated

  3. appreciated

  4. stabilized


Correct Option: B
Explanation:

Depreciation means decrease in value, or decline in price.

'Advice' is ______.

  1. a verb

  2. a noun

  3. an adjective

  4. both a verb and a noun


Correct Option: B
Explanation:

'Advise' is verb and 'advice' is a noun. So advice is what is given and act of giving advice is called advising.

Find the next term in the sequence: 7G, 11K, 13M, ______

  1. 15Q

  2. 17Q

  3. 15P

  4. 17P


Correct Option: B
Explanation:

Correct option is (2).

“India is a country of rich heritage and cultural diversity.” Which one of the following facts best supports the claim made in the above sentence?

  1. India is a union of 28 states and 7 union territories.

  2. India has a population of over 1.1 billion.

  3. India is home to 22 official languages and thousands of dialects.

  4. The Indian cricket team draws players from over ten states.


Correct Option: C
Explanation:

“India is a country of rich heritage and cultural diversity”. Statement showing India’s diversified cultural heritage which can be shown or expressed best by that India is a home to 22 official languages and thousands of dialects. This is expressing that 22 official language which are peculiar to specific region or social group showing itself rich heritage and cultural diversity of India.

In which of the following options will the expression P < M be definitely true?

  1. M < R > P > S

  2. M > S < P < F

  3. Q < M < F = P

  4. P = A < R < M


Correct Option: D
Explanation:

Correct option is (4).

The multi-level hierarchical pie chart shows the population of animals in a reserve forest. The correct conclusions from this information are:

(i) Butterflies are birds. (ii) There are more tigers in this forest than red ants. (iii) All reptiles in this forest are either snakes or crocodiles. (iv) Elephants are the largest mammals in this forest.

  1. (i) and (ii) only

  2. (i), (ii), (iii) and (iv)

  3. (i), (iii) and (iv) only

  4. (i), (ii) and (iii) only


Correct Option: D
Explanation:

(i)    Bird section contains Butterfly also (Right) (ii)   Tiger section covers more area on pi-chart the red-ant so they are in large number (Right) (iii)  There are only two kind of reptiles are in pie-chart; snakes & crocodile (Right) (iv)  Pi-chart did not representing about the size of animals so we can’t say anything about size (wrong)

If a function is continuous at a point,

  1. the limit of the function may not exist at the point

  2. the function must be derivable at the point

  3. the limit of the function at the point tends to infinity

  4. the limit must exist at the point and the value of limit should be same as the value of the function at that point


Correct Option: D
Explanation:

Correct option is (4).

Divergence of the vector field x2 zi + xyj – yz2 k at (1, - 1, 1) is

  1. 0

  2. 3

  3. 5

  4. 6


Correct Option: C
Explanation:

Correct option is (3).

Consider a single degree-of-freedom system with viscous damping excited by a harmonic force. At resonance, the phase angle (in degree) of the displacement with respect to the exciting force is

  1. 0

  2. 45

  3. 90

  4. 135


Correct Option: C
Explanation:

Correct option is (3).

A mass m1 of 100 kg travelling with a uniform velocity of 5 m/s along a line collides with a stationary mass m2 of 1000 kg. After the collision, both the masses travel together with the same velocity. The coefficient of restitution is

  1. 0.6

  2. 0.1

  3. 0.01

  4. 0


Correct Option: D
Explanation:

Correct option is (4).

Gear 2 rotates at 1200 rpm in counter clockwise direction and engages with Gear 3. Gear 3 and Gear 4 are mounted on the same shaft. Gear 5 engages with Gear 4. The numbers of teeth on Gears 2, 3, 4 and 5 are 20, 40, 15 and 30, respectively. The angular speed of Gear 5 is

  1. 300 rpm counterclockwise

  2. 300 rpm clockwise

  3. 4800 rpm counterclockwise

  4. 4800 rpm clockwise


Correct Option: A
Explanation:

Correct option is (1).

Which one of following is NOT correct?

  1. Intermediate principal stress is ignored when applying the maximum principal stress theory.

  2. The maximum shear stress theory gives the most accurate results amongst all the failure theories.

  3. As per the maximum strain energy theory, failure occurs when the strain energy per unit volume exceeds a critical value.

  4. As per the maximum distortion energy theory, failure occurs when the distortion energy per unit volume exceeds a critical value.


Correct Option: B
Explanation:

(A) In maximum principle stress theory, when the value of maximum principle stress is equal to that of yield point stress as found in a simple tensile test in which we don’t consider intermediate principle stress. (B) Maximum shear stress theory is well justified for ductile matarial because ductile material mostly fails by shear failure. (C) Maximum strain energy over estimate the elastic strength of ductile matarial. (D) As per maximum distortion energy theory, failure occurs when the distortion energy per unit volume exceeds a critical value.

Consider a long cylindrical tube of inner and outer radii, ri and ro, respectively, length, L and thermal conductivity, k. Its inner and outer surfaces are maintained at Ti and To, respectively (Ti > To). Assuming one-dimensional steady state heat conduction in the radial direction, the thermal resistance in the wall of the tube is

  1. $\frac{1}{2 \pi KL}1n \Big( \frac{r_i}{r_o} \Big)$

  2. $\frac{1}{2 \pi r_iL}$

  3. $\frac{1}{2 \pi KL}1n \Big( \frac{r_o}{r_i} \Big)$

  4. $\frac{1}{4 \pi KL}1n \Big( \frac{r_o}{r_i} \Big)$


Correct Option: C
Explanation:

Correct option is (3).

Consider a 3 x 3 real symmetric matrix S such that two of its eigen values are a $\neq$ 0, b $\neq$ 0 with respective eigenvectors $\begin{bmatrix} \ x1 \ \ x2 \ \ x3 \ \end{bmatrix}$, $\begin{bmatrix} \ y1 \ \ y2 \ \ y3 \ \end{bmatrix}$. If a $\neq$ b than x1 y1 + x2 y2 + x3 y3 equals

  1. a

  2. b

  3. ab

  4. 0


Correct Option: D
Explanation:

Correct option is (4).

For a gas turbine power plant, identify the correct pair of statements. P. Smaller in size compared to steam power plant for same power output Q. Starts quickly compared to steam power plant R. Works on the principle of Rankine cycle S. Good compatibility with solid fuel

  1. P, Q

  2. R, S

  3. Q, R

  4. P, S


Correct Option: A
Explanation:

(P) Gas turbine power plant consumes less space as compared to stream power plants because in steam power plants accessories like boiler, condenser coding tower adds more size and mass. (Q) Gas turbine power plant can be synchronized very fast as compared to steam power plants take too much time because it took more time to stabilize the temp in boiler. (R) Gas turbine power plants works on Joole-Brayton cycle. (S) Only liquid and gas fuel is used in gas turbine power plants.

Consider the turbulent flow of a fluid through a circular pipe of diameter, D. Identify the correct pair of statements.

I. The fluid is well-mixed. II. The fluid is unmixed. III. ReD < 2300 IV. ReD < 2300

  1. I, III

  2. II, IV

  3. II, III

  4. I, IV


Correct Option: D
Explanation:

For flow through a circular pipe, the flow will be _____. (A) Leminar flow Reynolds no. (Re) < 2300 Fluid flow is unmixed. (B) Turbulent flow Reynolds no. (Re) > 2300 Fluid flow is mixed.

The process utilizing mainly thermal energy for removing material is

  1. Ultrasonic Machining

  2. Electrochemical Machining

  3. Abrasive Jet Machining

  4. Laser Beam Machining


Correct Option: D
Explanation:

(A) Ultrasonic Machining (UCM) is a mechanical metal removing process for brittle material by using high frequency oscillations of shaped tool using abrasive slurry. (B) Electro Chemical Machining (ECM) uses electrical current to remove the metal relies on the principle of electrolysis for material removal. (C) Abrasive water jet machining is a process that uses a very high speed water jet mixed with abrasives to cut any type of matarial. (D) Laser beam machining utiliser the energy from the coherent light beam which first melt and then vaporise the tiny metal particles, in which thermal energy is used.

Cutting tool is much harder than the workpiece. Yet the tool wears out during the tool-work interaction, because

  1. extra hardness is imparted to the workpiece due to coolant used

  2. oxide layers on the workpiece surface impart extra hardness to it

  3. extra hardness is imparted to the workpiece due to severe rate of strain

  4. vibration is induced in the machine tool


Correct Option: C
Explanation:

Tool wears out during the tool-work interaction because extra hardness is imported to the workpiece due to severe rate of strain on the tool tip.

A minimal spanning tree in network flow models involves

  1. all the nodes with cycle/loop allowed

  2. all the nodes with cycle/loop not allowed

  3. shortest path between start and end nodes

  4. all the nodes with directed arcs


Correct Option: B
Explanation:

Correct option is (2).

Which one of the following pairs of equations describes an irreversible heat engine?

  1. $\oint SQ$ > 0 and $\oint \frac{SQ}{T}$ < 0

  2. $\oint SQ$ < 0 and $\oint \frac{SQ}{T}$ < 0

  3. $\oint SQ$ > 0 and $\oint \frac{SQ}{T}$ > 0

  4. $\oint SQ$ < 0 and $\oint \frac{SQ}{T}$ > 0


Correct Option: A
Explanation:

Correct option is (1).

The hot tearing in a metal casting is due to

  1. high fluidity

  2. high melt temperature

  3. wide range of solidification temperature

  4. low coefficient of thermal expansion


Correct Option: C
Explanation:

Hot tears in metal costing is a metallurgical defect which is also called hot cracking occurs as casting cools. This happens because the metal is weak when it is hot and residual stresses in the metal can cause the casting to fail as it cools. Proper mould design prevent this type of casting. So that uniform cooling rate for all parts can be maintained which reduce the range of solidification temperature.

Consider a simply supported beam of length, 50h, with a rectangular crosssection of depth, h, and width, 2h. The beam carries a vertical point load, P, at its mid-point. The ratio of the maximum shear stress to the maximum bending stress in the beam is

  1. 0.02

  2. 0.10

  3. 0.05

  4. 0.01


Correct Option: D
Explanation:

Correct option is (4).

The distance x from the end of the beam as shown in the figure. What would be the value of x so that the displacement at ‘A’ is equal to zero?

  1. 0.5L

  2. 0.25L

  3. 0.33L

  4. 0.66L


Correct Option: C
Explanation:

Correct option is (3).

A machine produces 0, 1 or 2 defective pieces in a day with associated probability of 1/6, 2/3 and 1/6, respectively. The mean value and the variance of the number of defective pieces produced by the machine in a day, respectively, are

  1. 1 and 1/3

  2. 1/3 and 1

  3. 1 and 4/3

  4. 1/3 and 4/3


Correct Option: A
Explanation:

Correct option is (1).

An annular disc has a mass m, inner radius R and outer radius 2R. The disc rolls on a flat surface without slipping. If the velocity of the center of mass is v, the kinetic energy of the disc is

  1. $\frac{9}{16}$ mv2

  2. $\frac{11}{16}$ mv2

  3. $\frac{13}{16}$ mv2

  4. $\frac{15}{16}$ mv2


Correct Option: C
Explanation:

Correct option is (3).

Consider two solutions x(t) = x1(t) and x(t) = x2 (t) of the differential equation $\frac{d^2x(t)}{dt^2}$ + x (t) = 0, t > 0, such that x1 (0) = 1,$\frac{dx_1(t)}{dt} \Big|{t -0} = 0, x_2(0) = 0, \frac{dx_2(t)}{dt}\Big|{t-0}$ = 1

The Wronskian W (t) = $\begin{bmatrix} \ x_1(t) & x_2(t) \ \ \frac{dx_1(t)}{dt} & \frac{dx_2(t)}{dt} \ \end{bmatrix}$ at t = $\frac{\pi}{2}$ is

  1. 1

  2. – 1

  3. 0

  4. 2$\pi$


Correct Option: A
Explanation:

Correct option is (1).

Consider a rotating disk cam and a translating roller follower with zero offset. Which one of the following pitch curves, parameterized by t, lying in the interval 0 to 2p, is associated with the maximum translation of the follower during one full rotation of the cam rotating about the center at (x, y) = (0, 0)?

  1. x(t) = cos t, y(t) = sint

  2. x(t) = cos t, y(t) = 2 sint

  3. x (t) $\frac{1}{2}$ + cos(t) = 1 +, y(t) = 2 sint

  4. x(t) $\frac{1}{2}$ + cos (t) = 1 +, y(t) = sint


Correct Option: C
Explanation:

Correct option is (3). $d_{max} = \sqrt{\frac{5}{4} + 1}\\ \hspace{0.9cm} = \sqrt{\frac{9}{4}}\\ \hspace{0.9cm} = 1.5 \hspace{0.5cm} \Rightarrow d_{D, max} = 1.5$

Match the casting defects (Group A) with the probable causes (Group B).

     
Group A
Group B
P Hot tears 1 Improper fusion of two streams of liquid metal
Q Shrinkage 2 Low permeability of the sand mould
R Blow holes 3 Volumetric contraction both in liquid and solid stage
4 Stresses in different regions of metal
  1. P - 1, Q - 3, R - 2, S - 4

  2. P - 4, Q - 3, R - 2, S - 1

  3. P - 3, Q - 4, R - 2, S - 1

  4. P - 1, Q - 2, R - 4, S - 3


Correct Option: B
Explanation:

(P) Hot tears is a metallurgical defect and occurs because of differential cooling rate, which creates stresses in the different regions of metal. (Q) Shrinkage occurs because of volumetric contraction as volume gets reduced during cooling. (R) Blow holes is a gas defect which occurs due to low permeability of sand mould. (S) Cold shut is pouring metal which appears due to improper fusion of two streams of liquid metal.

A manufacturer can produce 12000 bearing per day. The manufacturer received an order of 8000 bearings per day from a customer. The cost of holding a bearing in stock is Rs. 0.20 per month. Setup cost per production run is Rs. 500. Assuming 300 working days in a year, the frequency of production run should be

  1. 4.5 days

  2. 4.5 months

  3. 6.8 days

  4. 6.8 months


Correct Option: C
Explanation:

Correct option is (3).

A certain amount of an ideal gas is initially at a pressure p1and temperature T1. FIrst, it undergoes a constant pressure process 1-2 such that T2 = 3T1/4. Then, it undergoes a constant volume process 2-3 such that T3 = T1/2. The ratio of the final volume to the initial volume of the ideal gas is

  1. 0.25

  2. 0.75

  3. 1.0

  4. 1.5


Correct Option: B
Explanation:

Correct option is (2).

A solid sphere of radius r1 = 20 mm is placed concentrically inside a hollow sphere of radius r2 = 30 mm as shown in the figure.

The view factor F21 for radiation heat transfer is

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

  2. $\frac{4}{9}$

  3. $\frac{8}{27}$

  4. $\frac{9}{4}$


Correct Option: B
Explanation:

Correct option is (2).

A solid sphere of radius $r_1 = 20 mm$ placed inside concentrically inside a hollow sphere of radius $r_2 = 300mm$ as shown in figure.

Consider the given project network, where numbers along various activities represent the normal time. The free float on activity 4-6 and the project duration, respectively, are

  1. 2, 13

  2. 0, 13

  3. – 2, 13

  4. 2, 12


Correct Option: A
Explanation:

Correct option is (1).

Which pair of following statements is correct for orthogonal cutting using a singlepoint cutting tool? P. Reduction in friction angle increases cutting force Q. Reduction in friction angle decreases cutting force R. Reduction in friction angle increases chip thickness S. Reduction in friction angle decreases chip thickness

  1. P and R

  2. P and S

  3. Q and R

  4. Q and S


Correct Option: D
Explanation:

Correct option is (4).

The stress-strain curve for mild steel is shown in the figure given below. Choose the correct option referring to both figure and table.

  1. P - 1, Q - 2, R - 3, S - 4, T - 5, U - 6

  2. P - 3, Q - 1, R - 4, S - 2, T - 6, U - 5

  3. P - 3, Q - 4, R - 1, S - 5, T - 2, U - 6

  4. P - 4, Q - 1, R - 5, S - 2, T - 3, U - 6


Correct Option: C
Explanation:

(P) Proportionality limit : The highest stress at which stress is directly proportional to strain. (Q) Elastic limit : is the greatest stress at which the material can withstand without any measurable permanent strain after unloading. (R) Yield point/strength is the strength is the stress required to produce a small specific amount of deformation. (T) Ultimate tensile strength : is the maximum load point after it necking begins. (U) Failure point : It is the last point, after it specimen or material got fractured after necking. Stress-strain curve for mild steel.

A siphon is used to drain water from a large tank as shown in the figure below. Assume that the level of water is maintained constant. Ignore frictional effect due to viscosity and losses at entry and exit. At the exit of the siphon, the velocity of water is

  1. $\sqrt{2g(Z_O - Z_R)}$

  2. $\sqrt{2g(Z_P - Z_R)}$

  3. $\sqrt{2g(Z_O - Z_R)}$

  4. $\sqrt{2gZ_O}$


Correct Option: B
Explanation:

Correct option is (2).

A cylindrical blind riser with diameter d and height h, is placed on the top of the mold cavity of a closed type sand mold as shown in the figure. If the riser is of constant volume, then the rate of solidification in the riser is the least when the ratio h : d is

  1. 1 : 2

  2. 2 : 1

  3. 1 : 4

  4. 4 : 1


Correct Option: A
Explanation:

Correct option is (1).

An analytic function of a complex variable z = x + iy is expressed as f(z) = u (x, y) + iv (x, y), where i = $\sqrt{-1}$. If u (x, y) = x2 – y2, then expression for v (x, y) in terms of x, y and a general constant c would be

  1. xy + c

  2. $\frac{x^2 + y^2}{2}+c$

  3. 2xy + c

  4. $\frac{x^2 - y^2}{2}+c$


Correct Option: C
Explanation:

Correct option is (3).

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