All India Mechanical Engineering Group

Thermal conductivity of wood depends on
  • a)
    moisture
  • b)
    density
  • c)
    temperature
  • d)
    all of these
Correct answer is option 'D'. Can you explain this answer?

Sanskriti Chakraborty answered  •  1 hour ago
Thermal conductivity of wood is affected by several factors, including moisture content, density, and temperature. Let's discuss each of these factors in detail:

Moisture content:
- Wood is a hygroscopic material, which means it can absorb or release moisture from the environment.
- Moisture content in wood can affect its thermal conductivity because water has a much higher th
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All the three modes of heat transfer are involved in
  • a)
    melting of ice
  • b)
    Cooling of a small metal casting in a quenching bath
  • c)
    heat flow through the walls of a refrigerator
  • d)
    automobile engine equipped with a thermosyphon cooling system
Correct answer is option 'D'. Can you explain this answer?

Shreya Kulkarni answered  •  1 hour ago
Heat Transfer in Different Processes

Melting of ice:
- Heat transfer occurs through conduction as the warmer surroundings transfer heat to the ice causing it to melt
- Convection may also be involved as the melted water may move due to density differences

Cooling of a small metal casting in a quenching bath:
- Heat transfer occurs through conduction as the meta
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Consider the following statements pertaining to volumetric efficiency:
1. The. normal range of volumetric efficiency at full throttle for SI engines is more than that of CI engines.
2. Volumetirc efficiency is maximum at inlet mach number of 0.5.
3. Inlet valve mach index is related volumetric efficiency.
Which of these statements are correct
  • a)
     2 only
  • b)
    2 and 3
  • c)
    1, 2 and 3
  • d)
    1 and 3
Correct answer is option 'B'. Can you explain this answer?

Isha Nambiar answered  •  1 hour ago
Explanation:
Volumetric efficiency is the ratio of the actual mass of air drawn into the engine cylinder during the induction stroke to the mass of air that would occupy the same volume as the actual air at standard atmospheric conditions. It is an important parameter that determines the engine's ability to produce power.
Let us analyze the given statements one by one:
1. The norma
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Engine of different cylinder dimensions, power and speed are compared on the baiss of
  • a)
    maximum pressure
  • b)
    fuel consumption
  • c)
    mean effective pressure
  • d)
    unit power
Correct answer is option 'C'. Can you explain this answer?

Sai Reddy answered  •  1 hour ago
Comparing Engines Based on Mean Effective Pressure

Mean effective pressure (MEP) is a common metric used to compare the performance of different engines. MEP represents the average pressure that acts on the piston during the power stroke of an engine. Here's how MEP can be used to compare engines with different cylinder dimensions, power, and speed:

1. What is mean effective
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Consider the following parts of IC Engine:
1. Rocker arm
2. Follower
3. Cams
4. Camshaft
5. Crankshaft
Which among the above constitutes the part of valve train system?
  • a)
    1,2 and 3
  • b)
    1, 2, 3 and 4
  • c)
    2, 3 and 4
  • d)
    All of the above
Correct answer is option 'B'. Can you explain this answer?

Kajal Tiwari answered  •  1 hour ago
Valve Train System in IC Engine

The valve train system in an internal combustion engine controls the opening and closing of the engine's valves. It consists of several components, including:

1. Rocker arm: A rocker arm is a pivoting lever that allows the camshaft's motion to be transferred to the valve stem. It is usually mounted on a shaft that runs parallel to the camshaft.
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The intake charge in a diesel engine consists of
  • a)
    air alone
  • b)
    air + lubricating oil
  • c)
    air + fuel
  • d)
    air + fuel + lubricating oil
Correct answer is option 'A'. Can you explain this answer?

Jyoti Deshpande answered  •  1 hour ago
Intake Charge in a Diesel Engine

The intake charge in a diesel engine refers to the mixture of air and fuel that enters the combustion chamber during the intake stroke. This mixture is critical to the operation of the diesel engine, as it determines how efficiently the fuel is burned and how much power is produced.

Components of Intake Charge

The intake charge in a
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Most high speed compression engines operate on
  • a)
    Diesel cycle
  • b)
    Otto cycle
  • c)
    Dual combustion engine
  • d)
    Gas turbine
Correct answer is option 'C'. Can you explain this answer?

Jhanvi Datta answered  •  1 hour ago
Dual Combustion Engine:

A high-speed compression engine is an internal combustion engine that uses high compression ratios and high fuel injection pressures to achieve high power output. Most high-speed compression engines operate on the Dual Combustion Engine cycle.

The Dual Combustion Engine cycle is a modified version of the diesel cycle, which was developed to overcome th
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Pick the odd one
  • a)
    2-stroke Si engine
  • b)
    4-stroke Si engine
  • c)
    Cl engine
  • d)
    Gas turbine
Correct answer is option 'D'. Can you explain this answer?

Janhavi Choudhary answered  •  1 hour ago
Odd One Out: Gas Turbine

Explanation:
The given options are different types of engines. Let's discuss each one of them in brief.

1. 2-stroke Si engine:
- It is a type of internal combustion engine commonly used in small vehicles such as motorcycles, scooters, etc.
- It completes one cycle in two strokes of the piston (up and down).
- It has a simpler desig
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A cube subjected to three mutually perpendicular stress of equal intensity p expenses a volumetric strain
  • a)
    3p/ E × (2/m - 1)
  • b)
    3p/ E × (2 - m)
  • c)
    3p/ E × (1 - 2/m)
  • d)
    E/ 3× (2/m - 1)
Correct answer is option 'C'. Can you explain this answer?

Priyanka Tiwari answered  •  4 hours ago
Given: Poisson's ratio (ν) = 0.4

We need to find the ratio of Shear modulus (G) to Modulus of elasticity (E).

Formulae:

Shear modulus (G) = (3E(1 - 2ν)) / (2(1 + ν))

Modulus of elasticity (E) = (3K(1 - 2ν)) / (1 + ν)

Where K = Bulk modulus

Calculation:

Let's assume K = 1 for simplicity.

Modulus of elasticity (E
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Two closely coiled helical springs 'A' and 'B' are equal in all respects but the diameter of wire of spring 'A' is double that of spring 'B'. The stiffness of spring 'B' will be
  • a)
    one-sixteenth
  • b)
    one- eighth
  • c)
    one-fourth
  • d)
    one-half
Correct answer is option 'A'. Can you explain this answer?

Anjali Sengupta answered  •  4 hours ago
Explanation:
Stiffness of a spring is defined as the force required to produce unit displacement in the spring. Mathematically,
Stiffness (k) = F/x
where F is the force applied and x is the displacement produced.

Now, let's consider two springs A and B with the following properties:
- Both springs are equal in all respects except for the diameter of wire.
- The
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Modular ratio of the two materials is the ratio of
  • a)
    linear stress to linear strain
  • b)
    shear stress to shear strain
  • c)
    their modulus of elasticities
  • d)
    their modulus of rigidities
Correct answer is option 'C'. Can you explain this answer?

Dipika Kulkarni answered  •  5 hours ago
Modular Ratio of Materials

The modular ratio of two materials is a ratio of their elastic moduli. It is a very important concept in the mechanics of materials. The correct answer for the given question is option 'C' which states that the modular ratio of two materials is the ratio of their modulus of elasticities.

What is Modulus of Elasticity?

The modulus of elast
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The deformation of a bar under its own weight is ......the deformation, if the same body is subjected to a direct load equal to weight of the body.
  • a)
    equal to
  • b)
    half
  • c)
    double
  • d)
    quadruple
Correct answer is option 'B'. Can you explain this answer?

Ruchi Ahuja answered  •  5 hours ago
Deformation of a Bar under its own weight vs Direct Load

Deformation refers to the change in shape or size of an object when a force is applied to it. The amount of deformation depends on various factors, including the type of material, the magnitude of the force, and the direction of the force.

When a bar is subjected to its own weight, it experiences a certain amount of def
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Hook's law holds good up to
  • a)
    yield point
  • b)
    elastic limit
  • c)
    plastic limit
  • d)
    breaking point​
Correct answer is option 'B'. Can you explain this answer?

Sinjini Nambiar answered  •  6 hours ago
Hookes law is a law that states that the force required to extend or compress a spring by some distance is proportional to that distance. It applies to elastic materials.

Elastic limit:
- The elastic limit is defined as the maximum stress that a material can withstand without undergoing permanent deformation.
- Beyond this point, the material becomes permanently deformed, an
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Wherever some external system of forces acts on a body, it undergoes some deformation. As the body under goes some deformation, it sets up some resistance to the deformations. This resistance per unit area to deformation, is called
  • a)
    strain
  • b)
    stress
  • c)
    pressure
  • d)
    modulus of elasticity
Correct answer is option 'B'. Can you explain this answer?

Anjali Shah answered  •  6 hours ago
Stress and Deformation:

When an external force is applied to a body, it undergoes deformation. The deformation may be compressive, tensile or shear. Stress is the internal distribution of forces that balances the external forces applied to the body. It is the force per unit area acting on a body. Stress is a measure of the intensity of the internal forces acting in a body.

Ty
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The strain energy stored in a spring, when subjected to maximum load, without suffering permanent distortion, is known as
  • a)
    impact energy
  • b)
    proof resilience
  • c)
    proof stress
  • d)
    modulus of resilience
Correct answer is option 'B'. Can you explain this answer?

Mansi Kulkarni answered  •  12 hours ago
Proof Resilience:

Proof resilience is the maximum strain energy that a material can store without undergoing permanent deformation or failure. It is defined as the amount of energy per unit volume of material that can be absorbed when the material is subjected to a specific load without permanent deformation.

Calculation of Proof Resilience:

Proof resilience is cal
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The included angle of the V-blockis
  • a)
    45°
  • b)
    60°
  • c)
    90° '
  • d)
    120°
Correct answer is option 'C'. Can you explain this answer?

Mansi Rane answered  •  14 hours ago
°
b)60°
c)90°
d)120°

Without a diagram or additional information, it is impossible to determine the correct answer.

Surface plate is used to measure
  • a)
    flatness
  • b)
    straightness
  • c)
    roundness
  • d)
    squareness
Correct answer is option 'A'. Can you explain this answer?

Sanskriti Basu answered  •  14 hours ago
Surface plate is a precision measuring tool that is used in various industries to measure the flatness of surfaces. It is a flat, rigid, and smooth surface made of high-quality material such as granite or cast iron. The surface plate is designed to provide a reference surface for measuring the flatness of various objects.

Measurement of Flatness:
The flatness of an object can be d
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The units sold during the last four years were 940, 920, 970 and 880 units. The forecast for the fourth year was 917 units. If the forecast for the fifth year (using simple exponential smoothing) is equal to the forecast usin... more

Debolina Menon answered  •  15 hours ago
Forecasting using Simple Exponential Smoothing and Simple Moving Average

Given data:
- Last four years' units sold: 940, 920, 970, 880
- Forecast for fourth year: 917 units
- Actual units sold in fifth year: 900 units

Step 1: Finding the Exponential Smoothing Constant
To find the exponential smoothing constant, we need to compare the forecast for the fourt
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The deformation of a bar under its own weight as compared to that when subjected to a direct axial load equal to its own weight will be:
  • a)
    The same
  • b)
    One-fourth
  • c)
    Half
  • d)
    Double
Correct answer is option 'C'. Can you explain this answer?

Stuti Mishra answered  •  15 hours ago
Deformation of a Bar

Deformation refers to the change in the shape or size of an object under the influence of an external force. When a bar is subjected to an external force, it undergoes deformation. The amount of deformation depends on the magnitude of the external force and the properties of the material.

Deformation of a Bar under its Own Weight

When a bar is
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If a piece of material neither expands nor contracts in volume when subjected to stress, then the Poisson‟s ratio must be
  • a)
    Zero
  • b)
    0.25
  • c)
    0.33
  • d)
    0.5
Correct answer is 'D'. Can you explain this answer?

Nandini Basak answered  •  17 hours ago
Explanation:

Poisson's ratio is the ratio of lateral strain to longitudinal strain when a material is subjected to stress. It is denoted by the Greek letter nu (ν).

Mathematically, Poisson's ratio can be expressed as:

ν = - (lateral strain) / (longitudinal strain)

where negative sign indicates that lateral strain is opposite in direction to the applied
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A bar of length L tapers uniformly from diameter 1.1 D at one end to 0.9 D at the other end. The elongation due to axial pull is computed using mean diameter D. What is the approximate error in computed elongation?
  • a)
    10%
  • b)
    5%
  • c)
    1%
  • d)
    0.5%
Correct answer is option 'C'. Can you explain this answer?

Mrinalini Sharma answered  •  17 hours ago
Given:
- Length of bar, L
- Diameter at one end, 1.1D
- Diameter at the other end, 0.9D
- Elongation is computed using mean diameter, D

To find: Approximate error in computed elongation

Solution:
Let's assume that the axial pull is applied at the center of the bar, and the bar is in the elastic region of the stress-strain curve.

The elonga
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A bolt of uniform strength can be developed by
  • a)
    Keeping the core diameter of threads equal to the diameter of unthreaded portion of the bolt
  • b)
    Keeping the core diameter smaller than the diameter of the unthreaded portion
  • c)
    Keeping the nominal diameter of threads equal the diameter of unthr eaded portion of the bolt
  • d)
    One end fixed and the other end free
Correct answer is option 'A'. Can you explain this answer?

Mahi Kaur answered  •  17 hours ago
Explanation:

A bolt of uniform strength is a bolt that has the same strength throughout its length. The strength of a bolt is determined by the cross-sectional area of the bolt, which is a measure of the amount of material in the bolt. If the cross-sectional area of the bolt varies along its length, then the strength of the bolt will also vary along its length.

To develop a b
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A test specimen is stressed slightly beyond the yield point and then unloaded. Its yield strength will
  • a)
    Decrease
  • b)
    Increase    
  • c)
    Remains same
  • d)
    Becomes equal to ultimate tensile strength
Correct answer is option 'B'. Can you explain this answer?

Kritika Joshi answered  •  18 hours ago
Yield Strength and Yield Point

Yield strength is the amount of stress required to cause a material to deform plastically, meaning it won't return to its original shape when the stress is removed. Yield point is the point at which a material begins to deform plastically, and it is typically slightly lower than the yield strength.

Effect of Stressing Beyond Yield Point and Unlo
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An axial residual compressive stress due to a manufacturing process is present on the outer surface of a rotating shaft subjected to bending. Under a given bending load, the fatigue life of the shaft in the presence of the residual compressive stress is:
  • a)
    Decreased
  • b)
    Increased or decreased, depending on the external bending load
  • c)
    Neither decreased nor increased
  • d)
    Increased
Correct answer is 'D'. Can you explain this answer?

Stuti Bajaj answered  •  18 hours ago
Explanation:
The axial residual compressive stress on the outer surface of the rotating shaft due to the manufacturing process will have an effect on the fatigue life of the shaft when subjected to bending. The effect can be either positive or negative depending on the magnitude of the residual stress and the external bending load. The options can be analyzed as follows:

a) Decreas
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A rod of length L and diameter D is subjected to a tensile load P. Which of the following is sufficient to calculate the resulting change in diameter?
  • a)
    Young's modulus
  • b)
    Shear modulus 
  • c)
    Poisson's ratio
  • d)
    Both Young's modulus and shear modulus 
Correct answer is option 'D'. Can you explain this answer?

Ameya Kaur answered  •  19 hours ago
Calculation of Change in Diameter of a Rod under Tensile Load

When a rod of length L and diameter D is subjected to a tensile load P, there will be a change in its diameter. The magnitude of this change can be calculated using the following formula:

ΔD = (4P/πD²) * (1 - ν²) / E

Where ΔD is the change in diameter, P is the tensile load, D is the original diameter, ν
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Shell moulding can be used for.
  • a)
    producing milling cutters
  • b)
    making gold ornaments
  • c)
    Producing heavy and thick walled casting
  • d)
    producing thin casting
Correct answer is option 'D'. Can you explain this answer?

Dishani Desai answered  •  yesterday
Shell Moulding for Various Applications

Shell moulding is a casting process that involves the use of a resin-coated sand that is heated to create a shell-like mold. The molten metal is then poured into the mold to create the desired shape. Shell moulding is a versatile process that can be used for various applications. Here are some of the uses of shell moulding:

Producing Mi
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An engine is tested by means of a water brake at 1000 rpm. The measured torque-of the engine is 10000 Nm and the water consumption of the brake is 0.5 m3/s, its inlet temperature being 25°C. Assuming that the whole of the engine power is ultimately transferred into heat which is absorbed by the cooling water, what is the water temperature at exit?
  • a)
    22.5°C
  • b)
    23.5°C
  • c)
    24.5°C
  • d)
    25.5°C
Correct answer is option 'D'. Can you explain this answer?

Disha Nambiar answered  •  yesterday
°C and outlet temperature being 50°C. Determine the power output of the engine.

Assuming that the water brake absorbs all the power output of the engine, the power output of the engine can be calculated as:

Power output = torque x angular velocity

where torque = 10000 Nm and angular velocity = 2π x 1000/60 = 104.72 rad/s

Power output = 10000 Nm x 104.72
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The radius taken into consideration in calculating the stress in a hollow shaft subjected to torsion is
  • a)
    inner radius
  • b)
    outer radius
  • c)
    arithmetic mean radius
  • d)
    geometric mean radius
Correct answer is option 'B'. Can you explain this answer?

Nayanika Yadav answered  •  yesterday
Calculation of stress in a hollow shaft subjected to torsion

When a hollow shaft is subjected to torsion, stress is developed in the shaft due to the twisting action. The stress developed depends on various factors, including the radius of the shaft.

Radius taken into consideration

The radius taken into consideration in calculating the stress in a hollow shaft subj
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Torsion bars are in series
  • a)
    if same torque acts in each
  • b)
    if two equal torques (T) are applied in opposite direction at both end
  • c)
    if same shear stress gets developed in each
  • d)
    if they have same torsional rigidity
Correct answer is option 'B'. Can you explain this answer?

Saranya Saha answered  •  yesterday
Torsion Bars in Series

Torsion bars are a type of suspension system commonly used in vehicles. They are designed to provide a smooth ride by absorbing shocks and vibrations. Torsion bars work by twisting under load, which helps to absorb and dissipate energy. In this context, the term "in series" means that two or more torsion bars are connected in a series such that they work together
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Shear stress induced in a shaft subjected to tension will be
  • a)
    maximum at periphery and zero at center
  • b)
    maximum at center
  • c)
    uniform throughout
  • d)
    none of these
Correct answer is option 'D'. Can you explain this answer?

Shreya Choudhury answered  •  yesterday
Shear Stress in a Shaft Subjected to Tension

When a shaft is subjected to tension, it experiences both axial and shear stresses. The axial stress is due to the tensile force acting on the shaft, while the shear stress is due to the shearing force resulting from the torque applied to the shaft. The distribution of shear stress in a shaft subjected to tension depends on the geometry of th
... more

The value of shear stress which is induced in the shaft due to the applied couple varies
  • a)
    from maximum at the center to zero at circumference
  • b)
    from zero at the center to maximum at the circumference
  • c)
    from maximum at the center to minimum at the circumference
  • d)
    from minimum at the center to maximum at the circumference
Correct answer is option 'B'. Can you explain this answer?

Arshiya Dey answered  •  yesterday
Answer:

The correct option is b) from zero at the center to maximum at the circumference.

Explanation:

When a couple is applied to a shaft, it tends to twist the shaft. This twisting effect is resisted by the shear stress induced in the shaft. The distribution of shear stress along the cross-section of the shaft is not uniform. It varies from zero at the center to
... more
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