This GATE Mechanical Engineering (ME) question paper is
designed to help students assess their engineering knowledge
and problem-solving skills. It covers important topics such
as Engineering Mathematics, Engineering Mechanics, Strength
of Materials, Theory of Machines, Vibrations, Machine Design,
and other core mechanical engineering subjects.
The questions test conceptual understanding, numerical
accuracy, analytical thinking, and the application of
engineering principles. Students can practice multiple-choice
questions, revise important formulas, and develop effective
strategies for solving technical problems. Working through
the questions and studying their solutions can help identify
weak areas and improve preparation.
Regular practice with this paper can also improve time
management, confidence, and familiarity with GATE-style
questions. It is a useful study resource for Mechanical
Engineering students who want to strengthen their concepts,
revise essential topics, and prepare systematically for
the GATE examination.
Practice regularly, understand every solution, and prepare
confidently for GATE Mechanical Engineering.
GATE ME 2026 — Question 1
‘The team ______ more than 300 runs in 20 overs
___________ rains. However, some players needed to
improve their batting skills.’
Choose the option with the correct sequence of words
to fill the blanks.
Step-by-step explanation
Blank 1: “Scored” is the past-tense
form of “score” and fits the sentence describing
the team's performance.
Blank 2: “Despite” expresses contrast
and is followed by a noun or noun phrase. In the
given options, it is paired with “scored” in Option C.
Correct Answer: Option C — scored; despite
GATE ME 2026 — Question 2
If a positive real number x satisfies the following equation,
then the value of x is ________.
Q.3. The next figure (indicated by ‘?’) in the
sequence is:
→
→
→?
(A)
(B)
(C)
(D)
Solution:
Observe the movement of both symbols in the 4 × 3 grid:
The triangle moves one cell downward in the rightmost column.
The circle moves one cell downward in the leftmost column.
After reaching the bottom row, the circle returns to the top row.
In the next figure, the triangle is in the bottom-right cell
and the circle is in the second row of the leftmost column.
Therefore, the matching figure is Option A.
Q.6.
‘People are crowding around ___ pit into which ___ elephant
has fallen. I have never seen an elephant looking more
bewildered ___ miserable. Here it is in a most undignified
position, thrust into a pit and made to look up ___ a vast,
curiosity-struck crowd.’
Choose the option with the correct sequence of words to
fill the blanks.
(A)an; a; at; and
(B)a; an; and; at
(C)and; a; an; at
(D)at; a; an; and
Solution:
1. a pit: “Pit” begins with a consonant sound,
so we use “a”.
2. an elephant: “Elephant” begins with a vowel
sound, so we use “an”.
3. bewildered and miserable: “And” joins the
two adjectives describing the elephant.
4. look up at a crowd: The correct expression
here is “look up at”.
The completed sequence is a; an; and; at.
Therefore, the correct answer is Option B.
Q.7.
The table lists the unit selling price of five products P, Q,
R, S, and T. On a particular day, 250 items were sold with
the average selling price of Rs. 60. The following observations
were made:
(i) The quantity of S sold was twice that of T.
(ii) The quantity of R sold was thrice that of T.
(iii) The quantity of Q sold was twice that of T.
Product
P
Q
R
S
T
Unit selling price (Rs.)
100
50
40
60
60
What is the quantity of product P sold on that day?
(A)40
(B)50
(C)60
(D)70
Solution:
Let the quantity of product T sold be x.
According to the question:
T = x, S = 2x, R = 3x, Q = 2x
Total items sold = 250
Therefore,
P + 2x + 3x + 2x + x = 250 P = 250 − 8x ...(1)
Total selling amount = 250 × 60 = Rs. 15,000
Using the unit selling prices:
100P + 50(2x) + 40(3x) + 60(2x) + 60x = 15,000
Q.8.
Consider a string P of length l that is laid out as a
straight-line segment. Another string K is laid out as a
semicircular arc with string P as its diameter, as represented
in Figure (i). When both the strings are shortened by a length
x they can be re-arranged such that the shortened string K
forms a full circle with the shortened string P as its diameter,
as represented in Figure (ii). The value of x/l is ______.
Choose the correct option:
(A)π
(B)(π − 1) / 2π
(C)π / [2(π − 1)]
(D)π / (π − 1)
Solution:
Initial length of string P = l
Initial length of semicircular string K = πl/2
After shortening both strings by x:
Length of shortened P = l − x
Length of shortened K = πl/2 − x
The shortened string P becomes the diameter of the circle
formed by shortened string K.
Q.9.
The Roman senator Meritorius, his brother, his son, and his
daughter have varying oratory skill levels. They are seated
in rows and columns as shown in the figure with exactly one
person sitting in each box. It is known that:
(i) Meritorius’ daughter and his brother are seated in the same column.
(ii) His son is seated diagonally across the sibling of the worst orator.
(iii) The best and worst orators are seated in the same row.
Who is the best orator?
Seating Arrangement
Column 1
Column 2
Row 1
Brother
Meritorius
Row 2
Daughter
Son
(A)Meritorius
(B)Meritorius’ brother
(C)Meritorius’ son
(D)Meritorius’ daughter
Solution:
Step 1: Meritorius’ brother and daughter must
occupy the same column.
Step 2: The son is seated diagonally opposite
the sibling of the worst orator. Using this condition, the
brother and son occupy diagonal positions, while the daughter
and brother remain in the same column.
Step 3: The best and worst orators must be
seated in the same row. The arrangement places Meritorius and
his brother in Row 1, and the daughter and son in Row 2.
Therefore, the best orator is Meritorius’ brother.
Q.10.
Which one of the patterns labelled P, Q, R, and S is used to
generate the following figure?
Original figure required
Choose the correct option:
(A)P
(B)Q
(C)R
(D)S
Solution:
The original pattern must be compared with the four candidate
patterns to identify which one generates the complete figure.
The correct option has not been set because the detailed
pattern needs to be verified first.
(A)always perpendicular to the surface of constant φ
(B)always parallel to the surface of constant φ
(C)the minimum rate of change of scalar φ
(D)always zero
Solution:
The gradient of a scalar function is written as
∇φ.
The gradient points in the direction of the maximum rate
of increase of the scalar function. It is perpendicular
(normal) to a surface on which the scalar function remains
constant.
For a constant scalar surface:
φ = constant
Therefore, the gradient is perpendicular to that surface.
Q.15.
The exact solution of the following integral is represented
as n.
If m represents the numerically evaluated value of
the above integral using the Trapezoidal rule by considering
four equal subintervals in the range of x, then
(m − n) is:
n = ∫04
dx
1 + x
(A)0.074
(B)−0.074
(C)−0.003
(D)0.003
Step 1: Calculate the exact value (n)
Given:
n = ∫04 dx/(1 + x)
Integrating:
n = [ln(1 + x)]04
n = ln 5 − ln 1 = ln 5
Therefore:
n ≈ 1.609438
Step 2: Apply the Trapezoidal rule
Number of subintervals: N = 4
Interval width:
h = (4 − 0)/4 = 1
Let f(x) = 1/(1 + x). The values are:
x
f(x)
0
1
1
1/2
2
1/3
3
1/4
4
1/5
Trapezoidal rule:
m = h/2 [f(0) + 2f(1) + 2f(2) + 2f(3) + f(4)]
Substituting h = 1:
m = 1/2 [1 + 2(1/2 + 1/3 + 1/4) + 1/5]
m = 1/2 [1 + 13/6 + 1/5]
m = 101/60 ≈ 1.683333
Step 3: Calculate (m − n)
m − n = 1.683333 − 1.609438
m − n ≈ 0.073895
Rounded to three decimal places:
m − n ≈ 0.074
Therefore, the correct answer is
Option A — 0.074.
Q.16.
A horizontal disk has a radial frictionless slot in which
a small block is confined to slide. The disk turns
anticlockwise about its centre with a constant angular
velocity of 3 rad/s. If the block slides along the slot
with a constant speed of 0.2 m/s relative to the slot,
then the magnitude of Coriolis acceleration in m/s² is:
Coriolis acceleration = ?
(A)2.4 m/s²
(B)0.6 m/s²
(C)1.2 m/s²
(D)0.3 m/s²
Solution:
Given:
Angular velocity, ω = 3 rad/s
Relative velocity of block, vrel = 0.2 m/s
Step 1: Use the Coriolis acceleration formula
The magnitude of Coriolis acceleration is:
aC = 2ωvrel
Step 2: Substitute the given values
aC = 2 × 3 × 0.2
aC = 1.2 m/s²
Therefore, the correct answer is
Option C — 1.2 m/s².
Note: Options A and C have been swapped as requested.
GATE 2026 — Mechanical Engineering (ME) | Q.17
Q.17.
A gear train with five gears is shown in the figure below.
The number of teeth on each gear is N₁, N₂, N₃, N₄ and N₅.
The idler gear in this gear train is:
(A)Gear 4
(B)Gear 2
(C)Gear 3
(D)Gear 1
Solution:
An idler gear is an intermediate gear that transmits
rotational motion between gears. Its main role is to
transmit motion and change the direction of rotation;
it does not determine the overall gear ratio in a simple
gear train.
In the given arrangement, gear 4 is the intermediate
gear between gear 3 and gear 5. Therefore, gear 4 acts
as the idler gear.
Q.18.
In a single degree of freedom vibrating system with only
viscous damping, the critical damping coefficient is
350 N s/m and the damping coefficient is 35 N s/m.
The logarithmic decrement of the vibrating system is:
Critical damping coefficient, cc = 350 N·s/m
Damping coefficient, c = 35 N·s/m
(A)0.63
(B)1.26
(C)0.32
(D)1.89
Solution:
Step 1: Calculate the damping ratio
The damping ratio is given by:
ζ = c / cc
Substituting the values:
ζ = 35 / 350 = 0.1
Step 2: Use the logarithmic decrement formula
For an underdamped vibrating system:
δ = (2πζ) / √(1 − ζ²)
Substituting ζ = 0.1:
δ = (2π × 0.1) / √(1 − 0.1²)
δ = 0.6283 / √0.99
δ ≈ 0.6315
Rounding to two decimal places:
δ ≈ 0.63
Therefore, the correct answer is
Option A — 0.63.
GATE 2026 — Mechanical Engineering (ME) | Q.19
Q.19.
A closely coiled helical compression spring of mean coil
diameter D and wire diameter d, is loaded by
an axial force F.
The maximum shear stress developed in the wire is:
(A)8FDπd³+4Fπd²
(B)8FDπd³+2Fπd²
(C)16FDπd³+4Fπd²
(D)32FDπd³+4Fπd²
Solution:
A closely coiled helical spring loaded axially develops
shear stress due to the twisting moment and direct shear
force in the wire.
Step 1: Calculate the torsional shear stress
The twisting moment is:
T = FD/2
For a circular wire, the torsional shear stress is:
τt = 16T/(πd³)
Substituting T = FD/2:
τt = 8FD/(πd³)
Step 2: Calculate the direct shear stress
The cross-sectional area of the wire is:
A = πd²/4
Therefore, the direct shear stress is:
τd = F/A = 4F/(πd²)
Step 3: Calculate the maximum shear stress
Adding the torsional and direct shear stress contributions:
Q.20.
A column of length 2 m and a square cross-section of
20 mm × 20 mm is fixed at one end and free at the other end.
The value of Euler's critical load for the column is
(Take E = 200 GPa):
Pcr =
π²EI
(KL)²
(A)62.80 kN
(B)15.70 kN
(C)31.40 kN
(D)7.85 kN
Solution:
Step 1: Calculate the moment of inertia (I)
For a square cross-section of side b = 20 mm:
I = b⁴/12 = 20⁴/12
I = 13333.33 mm⁴
Converting into m⁴:
I = 1.3333 × 10⁻⁸ m⁴
Step 2: Use Euler's column formula
For a fixed-free column:
K = 2, L = 2 m
Young's modulus:
E = 200 GPa = 200 × 10⁹ N/m²
Euler's critical load is:
Pcr = π²EI/(KL)²
Substituting the values:
Pcr =
[π² × 200 × 10⁹ × 1.3333 × 10⁻⁸]/(2 × 2)²
Pcr ≈ 8224 N ≈ 8.22 kN
Important: Using the standard Euler formula
with K = 2 gives approximately 8.22 kN, not 7.85 kN.
The provided answer choices and the supplied solution image
indicate 7.85 kN, but these values do not match exactly.
Please verify the original question or its answer key.
Option A and Option D have been swapped as requested.
GATE ME 2026 — Question 21
A rectangular plate is fillet-welded to a gusset plate using two
parallel fillet welds. Each weld has a length l and fillet size
h. The allowable shear strength of the weld material is
τall. If a tensile load P acts perpendicular
to the direction of the welds, determine the critical load that can be
carried by the welds.
Solution
For a fillet weld, the effective throat thickness is:
Effective throat = h / √2
There are two parallel welds, each having length l.
Therefore, the total effective throat area of the two welds is:
A = 2 × l × (h / √2)
A = √2 h l
The maximum load that can be carried by the welds is:
P = τall × A
Therefore,
P = √2 h l τall
✓ Correct Answer: (A) √2 h l τall
GATE ME 2026 — Question 22
Worm gears are primarily used to transmit rotary motion between
two shafts whose axes are non-parallel and non-intersecting.
Which of the following represents this arrangement?
Solution
A worm gear arrangement consists of a worm and a worm wheel.
It is commonly used when the two shafts have axes that are
non-parallel and non-intersecting.
Therefore, among the given options, the correct choice is:
✓ Correct Answer: (A) Non-parallel and non-intersecting shafts
GATE ME 2026 — Question 23
For an ideal gas, two different processes start from the same
initial state 1 and end at states 2 and 3, respectively. The final
states 2 and 3 lie on the same isotherm. If P and h
represent pressure and specific enthalpy, respectively, which of
the following relations is correct?
Solution
States 2 and 3 lie on the same isotherm. Therefore, their
temperatures are equal:
T2 = T3
For an ideal gas, specific enthalpy depends only on temperature.
Therefore, equal temperatures mean equal specific enthalpies:
h2 = h3
Hence, the correct option is:
✓ Correct Answer: (C) h2 = h3
GATE ME 2026 — Question 24
A steady incompressible laminar flow passes through a 90° bend
placed on a horizontal surface. The bend has inner pressure
Pi and outer pressure Po. The fluid
enters the bend with average velocity V. Which of the following
statements is correct?
Solution
For flow through a curved path, the pressure increases from the
inner side of the bend toward the outer side.
Po > Pi
Therefore, the pressure at the outer side of the bend is greater
than the pressure at the inner side.
Hence, the correct answer is:
✓ Correct Answer: (B)
Po > Pi
GATE ME 2026 — Question 25
An ideal gas passes isothermally through a long horizontal
uniform cross-section pipe under steady flow. Consider that the
pressure gradient is sufficient for a finite change in the density
of the gas. If the flow of the gas is purely pressure driven and
subsonic throughout, then the average flow velocity
Solution
Since the gas is flowing through a uniform cross-section pipe,
the area of the pipe remains constant.
Continuity equation:
ρAV = constant
Since the cross-sectional area A is constant,
ρV = constant
For an isothermal ideal gas,
ρ = P / RT
As the gas flows through the pipe, the pressure decreases in the
flow direction. Therefore, the density ρ also decreases.
From the continuity relation
ρV = constant, a decrease in density must be accompanied
by an increase in velocity.
ρ ↓ ⇒ V ↑
Hence, the average flow velocity increases along the flow.
✓ Correct Answer: (A)
increases along the flow
GATE ME 2026 — Question 26
Bernoulli's equation CANNOT be applied between
Solution
Bernoulli's equation for steady, incompressible and inviscid flow
can generally be applied along a streamline.
P/ρ + V²/2 + gz = constant
along a streamline
For a rotational flow, the Bernoulli constant can be
different for different streamlines.
Therefore, Bernoulli's equation cannot be applied between
two arbitrary points in a rotational flow field if those points
are not necessarily on the same streamline.
Rotational flow
⇒ Bernoulli valid along the same streamline
On the other hand, for an irrotational flow, Bernoulli's
equation can be applied between any two arbitrary points in the
flow field.
Irrotational flow
⇒ Bernoulli valid between arbitrary points
Therefore, the statement where Bernoulli's equation
cannot be applied is:
✓ Correct Answer: (D)
any two arbitrary points in the flow field for steady
incompressible rotational flow
GATE ME 2026 — Question 27
A quiescent fluid at temperature T3 is confined
between two vertical parallel plates. While plate 1 is kept at
temperature T1 and plate 2 is maintained at temperature
T2, a velocity profile between the plates, as shown in
the figure below, is generated due to heat transfer. Which one of
the following options shows the correct relations among
T1, T2, and T3?
Solution
The velocity profile is produced because of natural convection
caused by the temperature difference between the two vertical
plates.
From the given velocity profile, the fluid moves upward near
plate 1 and downward near plate 2.
Hot fluid rises ↑ Cold fluid sinks ↓
Therefore, plate 1 must be hotter than the reference fluid
temperature:
T1 > T3
Similarly, near plate 2 the fluid moves downward, indicating that
plate 2 is colder than the reference fluid temperature:
T3 > T2
Combining both relations:
T1 > T3 > T2
Hence, the correct option after swapping A and B is:
✓ Correct Answer: (B)
T1 > T3 and T3 > T2
GATE ME 2026 — Question 28
For the isothermal expansion of an ideal gas in a piston cylinder system, the net heat supplied during the process is equal to the net work. Which one of the following statements is correct for the given process?
Solution
1. First Law Analysis:
For an ideal gas undergoing an isothermal process (T = constant), internal energy change is zero (ΔU = 0).
Q = ΔU + W ⇒ Q = W
Since heat supplied equals work done, it satisfies the First Law of Thermodynamics.
2. Second Law Analysis (Kelvin-Planck Statement):
The Kelvin-Planck statement applies to a thermodynamic cycle, not to a single expansion process. Converting heat entirely into work in a single non-cyclic process does not violate the Second Law.
Conclusion: The process is physically possible.
✓ Correct Answer: (A)
The process is possible.
GATE ME 2026 — Question 29
A hydraulic crane supports a mass of 500 kg with its
piston-cylinder actuator, inclined at 60° with horizontal,
as shown in the figure below. The diameter of the piston is
30 cm and gravitational acceleration is
10 m/s². Neglecting mass of the piston, the reading of the
pressure gage in kPa (gage) is
Solution
The piston has to support the component of the weight acting
along the inclined piston-cylinder actuator.
F = mg sin(60°)
Given:
m = 500 kg
g = 10 m/s²
θ = 60°
Therefore,
F = 500 × 10 × sin(60°)
F = 4330.13 N
The piston diameter is:
D = 0.30 m
A = πD²/4
A = π(0.30)²/4
A = 0.07069 m²
The gauge pressure is obtained from:
P = F/A
P =
4330.13 / 0.07069
P ≈ 61260 Pa
P ≈ 61.26 kPa
Hence, the correct answer after swapping A and D is:
✓ Correct Answer: (D)
61.26 kPa
GATE ME 2026 — Question 30
In relation to metal casting defects, match the following:
Defect
Description
P
Dross
I
Shallow blow found on a flat casting surface
Q
Scab
II
Lighter impurities appearing on the top surface
of a casting
R
Scar
III
A rough, thin layer of metal, protruding above
the casting surface, on top of a thin layer of sand
Choose the correct matching:
Solution
The three casting defects can be identified from their
characteristic appearances and locations.
1. Dross → II
Dross consists of oxides and other lighter impurities that
float and appear on the top surface of the casting.
2. Scab → III
A scab is a rough, thin layer of metal that protrudes above
the casting surface. It is associated with a thin layer of
sand beneath it.
3. Scar → I
A scar is a shallow blow or surface defect found on a
relatively flat casting surface.
Dross → II
Scab → III
Scar → I
Therefore:
P–II, Q–III, R–I
✓ Correct Answer: (A)
P–II, Q–III, R–I
GATE ME 2026 — Question 31
In additive manufacturing, STL files may contain several types
of geometric or topology-related problems. Which of the
following is not considered an STL file error?
Solution
An STL model represents a 3D object using a collection of
triangular facets. Problems in this triangular representation
can lead to errors during additive manufacturing.
1. Missing facet
If a required triangular surface is absent from the STL model,
the geometry becomes incomplete. Therefore, it can be treated
as an STL file error.
2. Non-manifold topology
Improper connections between surfaces or edges can produce
non-manifold geometry. Such topology problems are associated
with invalid STL geometry.
3. Degenerate facets
A triangular facet with invalid or collapsed geometry is known
as a degenerate facet. This is also a problem in the STL model.
4. Staircase effect
The staircase effect is mainly a consequence of the
layer-by-layer nature of additive manufacturing and the
orientation/resolution of the layers. It is therefore a
manufacturing surface effect rather than an STL file
geometric error.
✓ Correct Answer: (A)
Staircase effect
GATE ME 2026 — Question 32
Solution
The important requirement is that the fixture should not
interfere with the rotating slab milling cutter.
Step 1: Maximum permissible fixture height
The lowest point of the cutter is located at:
205 mm
above the reference surface.
Therefore, the fixture height must be slightly less than
205 mm.
H < 205 mm
Step 2: Select the most suitable option
The available values are:
210 mm, 200 mm, 150 mm and 70 mm.
210 mm is greater than 205 mm, so it would interfere with
the cutter.
Among the remaining values, 200 mm is the largest
possible fixture height and therefore provides the most
suitable support while maintaining clearance.
Maximum suitable H = 200 mm
✓ Correct Answer: (B)
H = 200 mm
GATE ME 2026 — Question 33
A surface profile is measured along a sampling length.
The profile contains several peaks and valleys with
different heights measured from the mean reference line.
Using the ten-point height average method, determine the
surface roughness value in μm.
Solution
Step 1: Ten-point height average
The ten-point height average is obtained by taking the
average of the five highest peaks and the five deepest
valleys, with the peak and valley contributions measured
from the mean line.
Step 2: Sum of five highest peaks
8.30 + 6.90 + 6.70 + 6.30 + 6.20
= 34.40 μm
Step 3: Sum of five deepest valleys
1.92 + 1.97 + 2.01 + 2.81 + 2.82
= 11.53 μm
Ten-point height average
= (34.40 − 11.53) / 5
= 22.87 / 5
= 4.574 μm
≈ 4.57 μm
✓ Correct Answer: (C)
4.57 μm
GATE ME 2026 — Question 34
A steel plate having yield strength of 550 MPa, is subjected to biaxial state of stress as σx = σ and σy = −2σ. Using distortion energy theory and considering the factor of safety as 2, the permissible value of σ that can be applied to the plate is ________ MPa (rounded off to 1 decimal place).
Answer:MPa
Solution
Given Data:
Yield Strength, Syt = 550 MPa
Principal Stress, σ1 = σ
Principal Stress, σ2 = −2σ
Factor of Safety, FOS = 2
1. Distortion Energy Theory (Von Mises Failure Criterion):
✓ Correct Answer: 103.9 (Acceptable Range: 103.5 to 104.5)
GATE ME 2026 — Question 35
A sphere of radius 5 mm is initially in equilibrium at 400 °C in a furnace. It is suddenly removed from the furnace and dipped in a well-stirred water bath at 20 °C, with a convection heat transfer coefficient of 500 W/(m2K). For the given range of temperatures, the thermophysical properties of the material of the sphere are: density ρ = 3000 kg/m3, thermal conductivity k = 10 W/(mK), and specific heat c = 1000 J/(kgK). Neglecting radiation heat transfer, the time required for the centre of the sphere to cool from 400 °C to 50 °C is ________ seconds (rounded off to 2 decimal places).
Answer:seconds
Solution
1. Biot Number Calculation (Validity of Lumped Parameter Analysis):
Characteristic length, Lc = r / 3 = 0.005 / 3 m
Bi = (h × Lc) / k = [500 × (0.005 / 3)] / 10 = 0.0833
Since Bi < 0.1, Lumped Heat Capacity System is applicable.
Since y(x, 0) = 10 e−2x, let us assume the solution is of the form:
y(x, t) = 10 e−2x + kt
3. Calculate Partial Derivatives:
∂y / ∂x = −2 × 10 e−2x + kt = −2y
∂y / ∂t = k × 10 e−2x + kt = ky
4. Substitute into Differential Equation:
−2y = 3(ky) + y
−2y − y = 3ky
−3y = 3ky
k = −1
5. Final Solution:
y(x, t) = 10 e−2x − t
✓ Correct Answer: (A) y(x, t) = 10 e−2x − t
GATE ME 2026 — Question 38 (2 Marks)
Let f(t) be a function of t defined for all positive values of t. The Laplace transform of f(t) denoted by L{f(t)} = ∫0∞ e−st f(t) dt, provided that the integral exists where s is a parameter which may be a real or complex number.
The Laplace transform of f(t) = sin(2t) sin(4t) is:
Solution
1. Trigonometric Expansion:
Using the product-to-sum identity: 2 sin(A) sin(B) = cos(A − B) − cos(A + B)
A student council of 10 members consists of two students from engineering school, three students from science school and five students from arts school. The university administration selects three students from the council at random. What is the chance that out of the selected students, two belong to the same school and the third belongs to a different school?
Solution
1. Total Sample Space:
Selecting 3 students from a total of 10 students (2 Engineering, 3 Science, 5 Arts):
Probability = Favorable Ways / Total Ways = 79 / 120
✓ Correct Answer: (D) 79 / 120
Q.40 Mechanical Engineering (ME) — 2 Marks
A cantilever beam of length L is subjected to a concentrated
load P and a moment M as shown in the figure below.
Neglecting the mass of the beam, which one of the following options
is the correct representation of the shear force diagram (SFD) and
bending moment diagram (BMD)?
Select the correct option:
Detailed Solution
Step 1: Beam ko samjhein
Beam left side par fixed hai aur right side par free hai.
Beam ki total length L hai.
Point load P beam ke middle mein, yani
L/2 distance par lag raha hai.
Free end par clockwise moment diya gaya hai:
M = PL/2.
Step 2: Shear Force Diagram (SFD)
Point load P sirf beam ke first half mein hai.
Isliye fixed support se lekar load P tak shear force ka
magnitude constant P rahega.
Load P ke baad koi transverse load nahi hai.
Isliye second half mein shear force:
V = 0
Therefore SFD mein pehle L/2 tak rectangle aur
uske baad zero hona chahiye.
Step 3: Free end par bending moment
Free end par directly moment diya gaya hai:
M = PL/2
Isliye free end par BMD ki value
PL/2 honi chahiye.
Step 4: Load P ke baad BMD
Point load P ke right side mein koi aur transverse load nahi hai.
Isliye shear force zero hai, aur jab shear force zero hota hai,
bending moment constant rehta hai.
BMD = PL/2
Therefore load P se free end tak BMD
constant PL/2 hona chahiye.
Step 5: Load P ke left side BMD
Ab fixed support se load P ki taraf aate hue
shear force constant P hai.
Constant shear force ka matlab bending moment
linearly vary karega.
Load point par moment PL/2 hai.
Fixed support tak distance L/2 hai.
Point load P ke moment contribution ki wajah se fixed end par
additional moment:
P × L/2 = PL/2
Isliye fixed end par total bending moment ka magnitude:
PL/2 + PL/2 = PL
✓ Final Answer: Option (B)
SFD mein first half mein magnitude P aur
second half mein zero hona chahiye.
BMD fixed end par PL, load point par PL/2
aur load point se free end tak constant PL/2 hona chahiye.
💡 Quick GATE Trick
SFD: Point load P ke baad shear zero.
BMD: Free end par applied moment = PL/2,
aur point load ki wajah se fixed end par additional PL/2.
Isliye fixed end = PL.
GATE ME 2026 — Question 41 (2 Marks)
Two structural members are connected by a hinge at D and externally loaded as shown in the figure below. A and B are roller supports, and C is a pin support. Neglecting the mass of the members, the magnitude of the vertical reaction force at C in kN is:
Step-by-Step Solution
1. Free Body Diagram & Equilibrium:
Hinge D par moment zero hota hai ($\sum M_D = 0$).
Right portion DC ko consider karne par, support C par vertical reaction force $V_C$ find ki jati hai.
System ke symmetry aur equilibrium condition ($\sum F_y = 0$) se total downward load $10\text{ kN}$ equal reactions me divide hota hai.
2. Calculation:
Vertical force balance: $V_C = 5\text{ kN}$.
✓ Correct Answer: Option (C) - 5 kN
GATE ME 2026 — Question 42 (2 Marks)
A 5 kg mass is suspended at the free end of an overhanging massless beam, having a pin support and a roller support, as shown in the figure below. Young’s modulus of the material of the beam is 200 GPa and area moment of inertia of the beam is 10−8 m4. The natural frequency of the beam in rad/s is:
A very long fin of a uniform square cross-section is replaced by another very long fin of a uniform circular cross-section of the same material. Assume uniform and identical heat transfer coefficient for both the fins. If the diameter of the circular fin is equal to the side length of the square fin, then the ratio of heat transfer rates before and after the replacement is:
Step-by-Step Solution
1. Heat Transfer Rate Formula for Infinitely Long Fin:
$$Q_{\text{fin}} = \sqrt{h \cdot P \cdot k \cdot A_c} \, (T_0 - T_\infty)$$
Since $h$, $k$, and $(T_0 - T_\infty)$ are constant for both fins:
$$Q_{\text{fin}} \propto \sqrt{P \cdot A_c}$$
2. For Square Fin (Before Replacement):
Side length = $a$
Perimeter ($P_1$) = $4a$
Cross-sectional Area ($A_{c1}$) = $a^2$
$P_1 \cdot A_{c1} = (4a)(a^2) = 4a^3$
3. For Circular Fin (After Replacement):
Diameter = $d = a$
Perimeter ($P_2$) = $\pi d = \pi a$
Cross-sectional Area ($A_{c2}$) = $\frac{\pi}{4} d^2 = \frac{\pi}{4} a^2$
W is the objective function of the dual of Z. k1, k2, k3, and k4 represent the corresponding dual variables.
Which one of the following options represents the correct form of W?
Step-by-Step Solution
Primal to Dual Conversion Rules:
Objective Function: Since Primal is Minimize Z, Dual will be Maximize W[cite: 10].
Dual Objective Coefficients: Equal to the RHS values of Primal constraints:[cite: 10]
Maximize W = 0.4 k₁ + 0.6 k₂ + 2.0 k₃ + 1.8 k₄[cite: 10]
First Dual Constraint (for x₁): Transpose x₁ coefficients with inequality ≤ 0.07 (coefficient of x₁ in Z):[cite: 10]
0.1 k₁ + 0.1 k₃ + 0.2 k₄ ≤ 0.07[cite: 10]
Second Dual Constraint (for x₂): Transpose x₂ coefficients with inequality ≤ 0.05 (coefficient of x₂ in Z):[cite: 10]
0.1 k₂ + 0.2 k₃ + 0.1 k₄ ≤ 0.05[cite: 10]
✓ Correct Answer: Option (A)
GATE ME 2026 — Question 47 (2 Marks)
Four jobs are on order in a factory. As on day 20 of the production calendar, the corresponding due date and work remaining to complete these jobs (in days) are given in the table below.
Job
Due date
Work remaining (in days)
M
26
5
N
24
10
O
28
10
P
31
5
Which job(s) has/have critical ratio less than unity?
Step-by-Step Solution
Critical Ratio (CR) Formula:
Critical Ratio = (Due Date - Current Date) / Work Remaining
Given Current Date = Day 20
Calculating Critical Ratio for Each Job:
Job M: CR = (26 - 20) / 5 = 6 / 5 = 1.2 (> 1)
Job N: CR = (24 - 20) / 10 = 4 / 10 = 0.4 (< 1)
Job O: CR = (28 - 20) / 10 = 8 / 10 = 0.8 (< 1)
Job P: CR = (31 - 20) / 5 = 11 / 5 = 2.2 (> 1)
Jobs with Critical Ratio less than unity (< 1) are Job N and Job O.
✓ Correct Answer: Option (A)
GATE ME 2026 — Question 48 (2 Marks)
A block of 50 kg mass is on an inclined plane. The block is connected to another hanging mass M by an inextensible massless string through two massless pulleys as shown in the figure below. The coefficient of static friction between the block and the inclined plane is 0.3. Neglecting pulley friction, the minimum value of M required to start the upward motion of the block is ________ kg (rounded off to 1 decimal place).
Step-by-Step Solution
1. Equilibrium along the inclined plane (for upward motion):
Total pulling force required along the incline ($F$):
F = m · g · sin(30°) + μ · m · g · cos(30°)
F = 50 × g × [sin(30°) + 0.3 × cos(30°)]
F = 50 × g × [0.5 + 0.3 × 0.8660]
F = 50 × g × [0.5 + 0.2598] = 50 × g × 0.7598 = 37.99 g N
2. Mechanical Advantage of the Pulley System:
The string wraps around a movable pulley on the 50 kg block, providing two tension segments pulling the block upwards:
2 · T = F ⇒ T = F / 2
3. Balancing with Hanging Mass M:
Tension in the string is created by the weight of mass M ($T = M · g$):
M · g = (37.99 · g) / 2 ⇒ M = 18.995 kg ≈ 19.0 kg
✓ Correct Answer Range: 18.8 to 19.2 kg (19.0 kg)
GATE ME 2026 — Question 49 (2 Marks)
A simply supported beam is subjected to an external point load P as shown in the figure below. The beam has a rectangular cross-section of 20 mm × 45 mm. A is a pin support and B is a roller support. The shear stress developed at point C, lying on the neutral axis of the beam, is 3 MPa. Neglecting the mass of the beam, the magnitude of the applied load is ________ kN (rounded off to 1 decimal place).
Step-by-Step Solution
1. Reaction at Support A ($R_A$):
Total beam span $L = 1 + 1 + 3 = 5\text{ m}$. Taking moments about Support B:
R_A × 5 = P × 3 ⇒ R_A = 0.6 P
2. Shear Force at Point C ($V_C$):
Point C is at $x = 1\text{ m}$ from support A (before load P):
V_C = R_A = 0.6 P
3. Maximum Shear Stress Formula for Rectangular Section:
Maximum shear stress occurs at the Neutral Axis ($\tau_{\text{max}} = \tau_{\text{NA}}$):
Given $\tau_{\text{NA}} = 3\text{ MPa} = 3\text{ N/mm}^2$, $b = 20\text{ mm}$, and $h = 45\text{ mm}$:
3 = 1.5 × (0.6 P / [20 × 45])
3 = 0.9 P / 900
0.9 P = 2700 ⇒ P = 3000 N = 3.0 kN
✓ Correct Answer Range: 2.9 to 3.1 kN (3.0 kN)
Q.50 Mechanical Engineering (ME) — 2 Marks
A rigid slender bar, AB, is sliding against two mutually perpendicular
frictionless walls, as shown in the figure below. The velocity of the
point A in the downward direction at a given instant is 6 m/s.
At that instant, the magnitude of absolute velocity of the midpoint G is
______ m/s (rounded off to 2 decimal places).
Detailed Solution
Step 1: Given Information
Point A vertical wall ke along downward direction mein move kar raha hai.
Question mein A ki velocity di hui hai:
vA = 6 m/s downward
Figure mein bar AB horizontal wall ke saath
45° ka angle bana rahi hai.
Step 2: 45° angle ka use
Corner se A tak ki vertical distance ko y maan lete hain
aur corner se B tak ki horizontal distance ko x maan lete hain.
Bar 45° par hai. Isliye ye
45°–45°–90° triangle hai.
Is triangle ki dono perpendicular sides equal hoti hain.
Therefore:
x = y
Step 3: Point B ki velocity
Bar rigid hai, matlab bar ki length change nahi hoti.
Isliye:
x2 + y2 = L2
Time ke respect mein differentiate karne par:
2xvB + 2yvA = 0
2 se divide karne par:
xvB + yvA = 0
Step 4: vB calculate karte hain
Hum upward direction ko positive maan rahe hain.
A downward move kar raha hai, isliye:
vA = −6 m/s
Ab relation mein value put karte hain:
xvB + y(−6) = 0
Aur kyunki x = y:
xvB − 6x = 0
x common lene par:
x(vB − 6) = 0
x zero nahi hai, therefore:
vB = 6 m/s
Matlab B bhi 6 m/s ki speed se horizontal direction mein move kar raha hai.
Step 5: Midpoint G ki velocity
G, bar AB ka exact midpoint hai.
Isliye midpoint ki velocity, A aur B ki velocities ka
vector average hogi.
vG = (vA + vB) / 2
B ki velocity horizontal 6 m/s hai.
Isliye G ka horizontal component:
vGx = 6 / 2 = 3 m/s
A ki downward velocity 6 m/s hai.
Isliye G ka vertical component:
vGy = 6 / 2 = 3 m/s
Isliye G ke paas do perpendicular velocity components hain:
3 m/s horizontal aur 3 m/s downward.
Step 6: G ki resultant velocity
Horizontal aur vertical components 90° par hain.
Isliye Pythagoras theorem use karenge.
vG =
√(vGx2 + vGy2)
Values put karte hain:
vG = √(32 + 32)
= √(9 + 9)
= √18
= 4.2426 m/s
Question mein answer ko 2 decimal places tak round karna hai.
✓ Final Correct Answer = 4.24 m/s
💡 Quick GATE Trick
45° position par A aur B ki speeds equal hoti hain:
6 m/s.
Midpoint par dono components half ho jaate hain:
3 m/s and 3 m/s.
vG
= √(32 + 32)
= √18
= 4.24 m/s
Q.51 Mechanical Engineering (ME) — 2 Marks
A cylindrical pressure vessel made of steel has diameter of
3 m and wall thickness of 15 mm. For steel,
Young's modulus and Poisson's ratio are 210 GPa and
0.3, respectively. The cylinder is designed such that
the allowable strain at the outer cylindrical surface is equal
to 0.00034. The permissible pressure in the tank is
______ kPa (rounded off to 1 decimal place).
Detailed Solution
Step 1: Hoop Stress aur Longitudinal Stress
Thin cylindrical pressure vessel ke liye hoop stress hota hai:
A welded square plate of 1 m × 1 m is subjected to
biaxial stress of magnitude 6.5 MPa and 25 MPa,
as shown in the figure below. The ratio of the normal stress
acting in the perpendicular direction of the weld to the shear
stress of the weld is ______
(rounded off to 2 decimal place )
Detailed Solution
Step 1: Weld ka orientation
Figure mein weld square plate ke diagonal ke along hai.
Isliye weld horizontal direction ke saath 45° ka angle
bana raha hai.
θ = 45°
Step 2: Normal Stress on the Weld
Weld plane par normal stress ke liye stress transformation
equation use karenge:
σn =
(σx + σy)/2
+
(σx − σy)/2 cos 2θ
Yahan:
σx = 6.5 MPa
σy = 25 MPa
θ = 45°
Since:
cos(2 × 45°) = cos 90° = 0
Therefore:
σn
=
(6.5 + 25) / 2
σn = 15.75 MPa
Step 3: Shear Stress on the Weld
Weld plane par shear stress:
τ =
−(σx − σy)/2
sin 2θ
θ = 45° hone ke karan:
sin(2 × 45°) = sin 90° = 1
Therefore, shear stress ka magnitude:
|τ|
=
|6.5 − 25| / 2
|τ| = 18.5 / 2
|τ| = 9.25 MPa
Step 4: Required Ratio
Question mein normal stress aur shear stress ka ratio poocha gaya hai:
Ratio =
σn / |τ|
Values put karte hain:
Ratio =
15.75 / 9.25
= 1.7027...
✓ Final Correct Answer = 1.70
💡 Quick GATE Trick
Jab weld 45° par ho, tab:
σn = (σx + σy) / 2
τ = |σx − σy| / 2
Isliye:
Ratio =
(6.5 + 25) / |6.5 − 25|
= 31.5 / 18.5
= 1.70
Q.53 Mechanical Engineering (ME) — 2 Marks
Water with a density of 1000 kg/m3 comes out of
an industrial condenser through a horizontal pipe of
15 cm radius at the flow rate of 4.5 m3/min.
The outlet of the pipe is connected to a coaxial diffuser of
0.5 m length using a flange to raise the pressure of water
to atmospheric condition without any backflow. The inner radius
r, in m, of the diffuser cross-section is expressed as
r = 0.15 + 0.4x2
where, x represents the axial distance of the diffuser in m,
from its inlet. Considering frictionless flow, the magnitude of the
force exerted by the diffuser on the flange is ______ N
(rounded off to 2 decimal places).
Detailed Solution
Step 1: Flow rate ko m3/s mein convert karte hain
Given flow rate:
Q = 4.5 m3/min
Therefore:
Q = 4.5 / 60
Q = 0.075 m3/s
Step 2: Diffuser ke inlet aur outlet radius
Diffuser ka inlet radius:
r1 = 0.15 m
Diffuser ki length 0.5 m hai. Isliye outlet par:
x = 0.5 m
Given relation:
r = 0.15 + 0.4x2
x = 0.5 put karne par:
r2
=
0.15 + 0.4(0.5)2
r2
=
0.15 + 0.10
r2 = 0.25 m
Step 3: Inlet aur outlet velocity
Cross-sectional area:
A = πr2
Inlet area:
A1 = π(0.15)2
= 0.0706858 m2
Continuity equation se:
V = Q / A
Therefore inlet velocity:
V1
=
0.075 / 0.0706858
V1 = 1.0610 m/s
Outlet area:
A2 = π(0.25)2
= 0.1963495 m2
Outlet velocity:
V2
=
0.075 / 0.1963495
V2 = 0.38197 m/s
Step 4: Inlet pressure find karte hain
Flow frictionless hai aur outlet par pressure atmospheric hai.
Gauge pressure ke terms mein:
p2 = 0
Horizontal diffuser ke liye Bernoulli equation:
p1/ρ + V12/2
=
p2/ρ + V22/2
p2 = 0 hone par:
p1
=
ρ/2
(V22 − V12)
Values put karte hain:
p1
=
1000/2
[(0.38197)2 − (1.06103)2]
p1 = −489.94 Pa
Negative gauge pressure ka matlab inlet par atmospheric pressure
se thoda kam pressure hai.
Step 5: Momentum equation
Mass flow rate:
ṁ = ρQ
ṁ = 1000 × 0.075
ṁ = 75 kg/s
Axial direction mein momentum equation:
p1A1
+
Fdiffuser
=
ṁ(V2 − V1)
Isliye diffuser dwara fluid par lagaya gaya force:
Question diffuser dwara flange par exerted force ka
magnitude pooch raha hai.
Newton's third law ke according flange par force ka magnitude
same hoga, direction opposite hogi.
✓ Final Correct Answer = 16.30 N
💡 Quick GATE Trick
Is question mein sabse important steps hain:
r2 = 0.15 + 0.4(0.5)2
= 0.25 m
V1 = 1.061 m/s
V2 = 0.382 m/s
p1 = −489.94 Pa
Momentum equation apply karne par force ka magnitude
16.30 N milta hai.
Q.54 Mechanical Engineering (ME) — 2 Marks
Two rectangular surfaces both having 1 m2 area are
placed perpendicular to each other with a common edge. One surface
is hot, having a temperature of 1000 K and an emissivity of
0.4, while the other is insulated and in radiant balance with
a large surrounding room at 300 K. If the fraction of radiation
leaving the hot surface which reaches the other surface is 0.2,
then the equivalent value for the radiation heat loss from the hot
surface is ______ W/m2(rounded off to 2 decimal places).
Detailed Solution
Step 1: Black-body emissive power
Radiation heat transfer ke liye Stefan-Boltzmann law use karenge:
Eb = σT4
Hot surface ke liye:
Eb1
=
5.67 × 10−8(1000)4
Eb1 = 56700 W/m2
Surrounding room ke liye:
Eb3
=
5.67 × 10−8(300)4
Eb3 ≈ 459.27 W/m2
Step 2: View factors
Hot surface se radiation ka 0.2 fraction second surface
tak pahunchta hai.
F12 = 0.2
Isliye remaining radiation surrounding room tak jayega:
F13 = 1 − 0.2 = 0.8
Dono surfaces ka area equal hai, isliye reciprocity se:
F21 = F12 = 0.2
F23 = 0.8
Step 3: Insulated surface ki condition
Second surface insulated hai aur radiant balance mein hai.
Isliye uska net radiation heat transfer zero hoga.
q2 = 0
Is condition ka matlab hai ki second surface jitni radiation
absorb karti hai, utni hi radiation emit karti hai.
J2 = G2
Irradiation:
G2
=
0.2J1 + 0.8Eb3
Therefore:
J2
=
0.2J1
+
0.8Eb3
Step 4: Hot surface ki radiosity
Radiosity equation:
J1
=
εEb1
+
(1 − ε)G1
Hot surface ki irradiation:
G1
=
0.2J2
+
0.8Eb3
ε = 0.4 hone par:
J1
=
0.4Eb1
+
0.6G1
Step 5: Simultaneous equations solve karte hain
Upar ki equations ko combine karne par:
J1
=
0.4(56700)
+
0.6[0.2J2 + 0.8(459.27)]
Aur:
J2
=
0.2J1
+
0.8(459.27)
Equations solve karne par:
J1 ≈ 23509 W/m2
J2 ≈ 5069 W/m2
Step 6: Hot surface se net radiation heat loss
Hot surface ka net radiation heat loss:
q1
=
J1 − G1
Alternatively, non-black surface ke liye:
q1
=
ε/(1 − ε)
×
(Eb1 − J1)
Values substitute karte hain:
q1
=
0.4/0.6
×
(56703.74 − 23510.30)
q1 = 22128.96 W/m2
✓ Final Correct Answer = 22128.96 W/m²
💡 Quick GATE Trick
Insulated surface ke liye sabse important condition:
q2 = 0
⇒
J2 = G2
Is condition ko radiosity equations ke saath solve karne par
hot surface ka net radiation heat loss:
22128.96 W/m²
Q.55 Mechanical Engineering (ME) — 2 Marks
Convective heat transfer coefficients for Fluid 1 and Fluid 2 in a
heat exchanger, as shown in the figure below, are
50 W/(m2K) and 80 W/(m2K),
respectively. The inner tube is made of a material which has a
thermal conductivity of 386 W/(mK) for the given range of
temperatures in the heat exchanger. The length of the heat
exchanging surface, the inside radius of the inner tube, and
thickness of the inner tube are 1 m, 10 mm, and
1 mm, respectively. Considering no heat exchange between
the outer tube and the surrounding, the heat transfer rate for
the heat exchanger is ______ W
(rounded off to 1 decimal place).
Detailed Solution
Step 1: Temperature Difference
Figure se heat exchanger ke dono ends par temperature
difference calculate karte hain.
Ek end par:
ΔT1 = 60 − 30 = 30°C
Doosre end par:
ΔT2 = 40 − 20 = 20°C
Step 2: Log Mean Temperature Difference
Counter-flow heat exchanger ke liye:
ΔTlm
=
(ΔT1 − ΔT2)
/
ln(ΔT1/ΔT2)
Values put karte hain:
ΔTlm
=
(30 − 20) / ln(30/20)
ΔTlm
=
10 / ln(1.5)
ΔTlm ≈ 24.66 K
Step 3: Tube Dimensions
Inner radius:
ri = 10 mm = 0.010 m
Tube thickness = 1 mm, therefore outer radius:
ro
=
10 + 1
= 11 mm
= 0.011 m
Length:
L = 1 m
Step 4: Heat Transfer Resistance
Cylindrical tube ke liye total thermal resistance:
Rtotal
=
1/(h2 Ai)
+
ln(ro/ri)/(2πkL)
+
1/(h1 Ao)
Inner aur outer areas:
Ai = 2πriL
Ai
=
2π(0.010)(1)
Ai = 0.06283 m²
Ao
=
2π(0.011)(1)
Ao = 0.06912 m²
Step 5: Individual Resistances
Fluid 2 side resistance:
Ri
=
1/(80 × 0.06283)
Ri ≈ 0.19894 K/W
Tube wall resistance:
Rwall
=
ln(0.011/0.010)
/
(2π × 386 × 1)
Rwall ≈ 0.000039 K/W
Fluid 1 side resistance:
Ro
=
1/(50 × 0.06912)
Ro ≈ 0.28937 K/W
Step 6: Total Resistance
Rtotal
=
0.19894 + 0.000039 + 0.28937
Rtotal ≈ 0.48835 K/W
Step 7: Heat Transfer Rate
Heat transfer rate:
Q = ΔTlm / Rtotal
Values substitute karte hain:
Q
=
24.66 / 0.48835
Q ≈ 50.5 W
✓ Final Correct Answer = 50.5 W
💡 Quick GATE Trick
Is question mein tube wall ki thermal resistance bahut chhoti hai,
kyunki k = 386 W/(mK) hai. Main resistance convection
sides ki hai.
Q = ΔTlm / Rtotal
Q ≈ 50.5 W
Q.56 Mechanical Engineering (ME) — 2 Marks
A liquid comes out of the reactor of a chemical plant at
250°C temperature with a flow rate of 100 LPM.
The ambient temperature is 25°C. Density and specific heat
of the liquid remain constant at 1000 kg/m3 and
4.18 kJ/kg·K, respectively, for the given range of
temperature. The rate of exergy associated with the hot liquid
stream at the exit of the plant is ______ kW
(rounded off to 2 decimal places).
Detailed Solution
Step 1: Mass Flow Rate
Liquid ka volumetric flow rate:
V̇ = 100 LPM
Since,
1 m3 = 1000 L,
V̇
=
100 / 1000 × 1/60
V̇ = 0.0016667 m3/s
Mass flow rate:
ṁ = ρV̇
ṁ
=
1000 × 0.0016667
ṁ = 1.6667 kg/s
Step 2: Temperatures in Kelvin
Hot liquid temperature:
T = 250 + 273.15
T = 523.15 K
Ambient temperature:
T0 = 25 + 273.15
T0 = 298.15 K
Step 3: Exergy per unit mass
Constant specific heat ke liye thermal exergy:
ex
=
cp
[(T − T0)
−
T0 ln(T/T0)]
Given:
cp = 4.18 kJ/kg·K
T = 523.15 K
T0 = 298.15 K
Step 4: Values substitute karte hain
ex
=
4.18
[(523.15 − 298.15)
−
298.15 ln(523.15/298.15)]
ex
=
4.18
[225
−
298.15 ln(1.7548)]
ex
≈
239.76 kJ/kg
Step 5: Rate of Exergy
Exergy rate:
Ėx
=
ṁ ex
Therefore:
Ėx
=
1.6667 × 239.76
Ėx
≈
399.60 kW
✓ Final Correct Answer = 399.60 kW
💡 Quick GATE Formula
Liquid stream ki thermal exergy ke liye directly:
Ėx
=
ṁ cp
[(T − T0)
−
T0 ln(T/T0)]
Yahan temperature ko Kelvin mein lena hai.
Q.57 Mechanical Engineering (ME) — 2 Marks
A rigid closed vertical cylindrical vessel of 15 cm diameter
contains 5 kg water at 80°C with 10% quality.
The water is heated till its temperature reaches 130°C.
Considering only a horizontal separated interface between liquid
and vapor, the dip in the liquid level after heating is ______ cm
(rounded off to 2 decimal places).
Properties of water at various saturation temperatures are given
in the table below.
Temperature T (°C)
Specific volume vf (m³/kg)
Specific volume vg (m³/kg)
Specific internal energy uf (kJ/kg)
Specific internal energy ug (kJ/kg)
80
0.001029
3.4053
334.97
2481.60
130
0.001070
0.66808
546.10
2539.50
T, vf, vg, uf and ug
are temperature, specific volume, and specific internal energy,
respectively. Subscripts f and g represent saturated
liquid and saturated vapor, respectively.
Detailed Solution
Step 1: Initial specific volume
Initially water is at 80°C with quality
x1 = 0.10.
Two-phase mixture ka specific volume:
v1
=
vf
+
x1(vg − vf)
v1
=
0.001029
+
0.1(3.4053 − 0.001029)
v1 = 0.3414561 m³/kg
Step 2: Total volume of the rigid vessel
Rigid vessel mein total volume constant rahega.
V = mv1
V
=
5 × 0.3414561
V = 1.7072805 m³
Step 3: Final quality at 130°C
Rigid vessel ke liye specific volume constant rahega:
Rigid vessel mein total specific volume constant rahega,
lekin temperature badhne par vapor ka specific volume decrease
hone ki wajah se final quality change hoti hai.
v1 = v2
x2
=
(v − vf2)
/
(vg2 − vf2)
Q.58 Mechanical Engineering (ME) — 2 Marks
An inward flow reaction turbine, having an outer diameter of
1 m, runs at 600 RPM. The normal component of
absolute velocity at inlet is 10 m/s. If the guide blade
angle is 15°, then the inlet vane angle of the runner is
______ degree
(rounded off to 1 decimal place).
Detailed Solution
Step 1: Blade speed at inlet
Inlet outer diameter:
D1 = 1 m
Turbine speed:
N = 600 RPM
Blade speed:
u1
=
πD1N / 60
u1
=
π × 1 × 600 / 60
u1 = 31.416 m/s
Step 2: Whirl component of absolute velocity
Normal component of absolute velocity:
Vf1 = 10 m/s
Guide blade angle:
α = 15°
Velocity triangle se:
tan α
=
Vf1 / Vw1
Therefore:
Vw1
=
Vf1 / tan 15°
Vw1
=
10 / tan 15°
Vw1 = 37.321 m/s
Step 3: Relative velocity at inlet
Relative velocity ka tangential component:
Vw1 − u1
Values substitute karne par:
Vw1 − u1
=
37.321 − 31.416
= 5.905 m/s
Step 4: Inlet vane angle
Inlet vane angle ko β1 maan lete hain.
Velocity triangle se:
tan β1
=
Vf1
/
(Vw1 − u1)
Values put karte hain:
tan β1
=
10 / 5.905
tan β1
≈
1.6935
Therefore:
β1
=
tan−1(1.6935)
β1 ≈ 59.4°
✓ Final Correct Answer = 59.4°
💡 Quick GATE Formula
Vw1
=
Vf1 cot α
tan β1
=
Vf1
/
(Vw1 − u1)
Yahan α = 15°, Vf1 = 10 m/s aur
u1 = 31.416 m/s.
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Q.59 Mechanical Engineering (ME) — 2 Marks
In a deep drawing operation of a rectangular sheet metal,
30% stretching in length results in
15% reduction in thickness.
Assuming volume constancy, the normal anisotropy of the
sheet metal is ________
(rounded off to 2 decimal places).
The actual demand for castings in a factory is
500 units and 635 units for the months of
January 2026 and February 2026, respectively.
The forecasted demand for January 2026 is
250 units and smoothing constant is 0.7.
Using the exponential smoothing method, the forecast of the
demand for castings in March 2026 is ________
units (in integer).
Detailed Solution
Step 1: Exponential smoothing formula
Ft+1
=
αAt
+
(1 − α)Ft
Where:
α = smoothing constant = 0.7
At = Actual demand
Ft = Previous forecast
Step 2: Forecast for February 2026
January actual demand = 500 units
January forecast = 250 units
FFeb
=
0.7(500) + (1 − 0.7)(250)
=
350 + 0.3(250)
=
350 + 75
FFeb = 425 units
Step 3: Forecast for March 2026
February actual demand = 635 units
February forecast = 425 units
FMar
=
0.7(635) + (1 − 0.7)(425)
=
444.5 + 0.3(425)
=
444.5 + 127.5
FMar = 572 units
✓ Final Correct Answer = 572 units
💡 Quick GATE Formula
Ft+1
=
αAt
+
(1 − α)Ft
Pehle February ka forecast 425 nikalenge,
phir February actual demand 635 ko use karke
March ka forecast 572 units milega.
Q.61 Mechanical Engineering (ME) — 2 Marks
The inventory holding cost of an item is
₹0.50 per unit per month and the ordering cost per order
is ₹550. A stockist needs to supply
10000 units of the item per year to the customers.
Assume demand is fixed and shortage cost is infinite.
Using the classical economic order quantity (EOQ) model,
the optimal size is ________ units per order
(rounded off to nearest integer).
Detailed Solution
Step 1: Given data
Annual demand,
D = 10000 units/year
Ordering cost,
S = ₹550/order
Holding cost =
₹0.50 per unit per month
Step 2: Convert holding cost into annual cost
Since the holding cost is given per month:
H = 0.50 × 12
H = ₹6 per unit per year
Step 3: Classical EOQ formula
EOQ = √(2DS/H)
Substituting the given values:
EOQ
=
√[(2 × 10000 × 550) / 6]
=
√(11000000 / 6)
=
√1833333.33
Step 4: Calculate optimal order size
EOQ ≈ 1354.01 units
EOQ ≈ 1354 units
✓ Final Correct Answer = 1354 units
💡 Quick GATE Formula
EOQ = √(2DS/H)
Hannual
=
Hmonthly × 12
Yahan D = 10000, S = ₹550 aur
H = ₹0.50 × 12 = ₹6/year.
Q.62 Mechanical Engineering (ME) — 2 Marks
A metal has FCC crystal structure with
2.71 g/cm³ density and 26.98 g/mol
atomic weight. The Avogadro's number is
6.023 × 1023.
The atomic radius of the metal is ________ nm
(rounded off to 2 decimal places).
Detailed Solution
Step 1: Given data
Density,
ρ = 2.71 g/cm³
Atomic weight,
M = 26.98 g/mol
Avogadro's number,
NA = 6.023 × 1023
Crystal structure = FCC
Step 2: Number of atoms per unit cell
For an FCC crystal structure:
n = 4 atoms/unit cell
Step 3: Find lattice parameter
Density relation is:
ρ = nM / (NAa³)
Therefore:
a³
=
nM / (ρNA)
a³
=
(4 × 26.98)
/
(2.71 × 6.023 × 1023)
a ≈ 4.044 × 10−8 cm
Step 4: Relation between atomic radius and lattice parameter
For FCC structure, atoms touch along the face diagonal.
4r = √2 a
r = a / (2√2)
Substituting the value of a:
r
=
(4.044 × 10−8)
/
(2√2)
r ≈ 1.430 × 10−8 cm
Step 5: Convert into nanometres
1 cm = 107 nm
r
=
1.430 × 10−8 × 107
r ≈ 0.143 nm
r ≈ 0.14 nm
✓ Final Correct Answer = 0.14 nm
💡 Quick GATE Formula
ρ = nM / (NAa³)
FCC: n = 4
r = a / (2√2)
FCC structure में 4 atoms/unit cell होते हैं और
atomic radius के लिए r = a/(2√2) का relation use करते हैं.
Q.63 Mechanical Engineering (ME) — 2 Marks
During orthogonal turning by using a single point cutting tool,
feed rate is 0.24 mm/rev. The uncut chip thickness is
0.23 mm. The shear angle, tangential force component,
and radial force component are 20°, 800 N,
and 150 N, respectively. The value of shear force is
________ N (rounded off to 2 decimal places).
Detailed Solution
Step 1: Given data
Feed rate,
f = 0.24 mm/rev
Uncut chip thickness,
t1 = 0.23 mm
Shear angle,
φ = 20°
Tangential force,
Fc = 800 N
Radial force,
Fr = 150 N
Step 2: Shear force relation
For orthogonal cutting, the shear force is obtained from
the force components using the Merchant force circle:
Fs
=
Fc cos φ
−
Fr sin φ
Step 3: Substitute the values
Fs
=
800 cos 20°
−
150 sin 20°
=
800(0.93969)
−
150(0.34202)
=
751.75
−
51.30
Step 4: Calculate shear force
Fs = 700.45 N
✓ Final Correct Answer = 700.45 N
💡 Quick GATE Formula
Fs
=
Fc cos φ
−
Fr sin φ
Yahan Fc = 800 N,
Fr = 150 N aur
φ = 20°.
Q.64 Mechanical Engineering (ME) — 2 Marks
A drill bit during its lifetime can produce
150 through holes in a plate at a drill-speed of
200 RPM. If the drill-speed increases to
300 RPM, then it can produce 60 through holes
in the same plate before the drill bit fails.
Assume all other parameters remain constant.
The value of the exponent n in Taylor's tool life
equation is ________
(rounded off to 2 decimal places).
Detailed Solution
Step 1: Given data
At 200 RPM:
T1 = 150 holes
At 300 RPM:
T2 = 60 holes
N1 = 200 RPM
N2 = 300 RPM
Step 2: Taylor's tool life equation
Taylor's tool life equation is:
VTn = C
Since all other parameters remain constant:
N1T1n
=
N2T2n
Step 3: Substitute the values
200(150)n
=
300(60)n
(150/60)n
=
300/200
(2.5)n
=
1.5
Step 4: Find the value of n
Taking logarithm on both sides:
n log(2.5) = log(1.5)
n
=
log(1.5) / log(2.5)
n
≈
0.4055 / 0.9163
Step 5: Final calculation
n ≈ 0.44
✓ Final Correct Answer = 0.44
💡 Quick GATE Formula
V Tn = C
n =
log(V1/V2)
/
log(T2/T1)
Yahan tool life ko number of holes ke proportional maana gaya hai,
kyunki hole size aur machining conditions same hain.
Q.65 Mechanical Engineering (ME) — 2 Marks
The activities of a PERT network and their corresponding
activity time estimates (in weeks), i.e., optimistic
(to), most likely
(tm), and pessimistic
(tp), are given in the table below.
The expected project length is ________ weeks
(in integer).
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