The ultimate tensile strength and yield strength of most of the metals, when temperature falls from $$0$$ to $$-150^\circ C$$ will
ISRO Scientist or Engineer Mechanical 2008
For the following questions answer them individually
“Troosite” is obtained when
Induction hardening is the process of
Heavy water is used in atomic powerplants as
Which one is not the purpose of heat treatmentof steels?
A cold chisel is made of
A body which is permanently deformedis said to have undergone
The defect responsible for the phenomenaofslip, by which most metals deform plastically, is known as
With a punch for which the maximum crushingstress is 4 times the maximum shearing stress of the plate, the biggest hole that can be punchedin the plate would be of diameter equal to
For traction applications, the type of motor best suited is
On loading a ductile material in excess of a certain value, gradual increase in elongation occurs with time. Such phenomenon is known as
The failure occurs at a point in a member, when the maximum shear stress in a bi-axial stress system reaches the shearstress at elastic limit in simple tension test, This is according to
The function of a washer is
Surface endurance limit of gear material depends on its
A double strap butt joint is always in
If $$y = \tan^{-1}\frac{2x}{1 - x^2}$$, then $$\frac{dy}{dx}$$ is
Rivets are made of
The purpose of providing multiple collars on a flat collar pivot bearingis to
Angle of dwell of cam is defined as the angle
The supply of working fluid to the engine to suit the load conditions is controlled by
A pantograph is a device that reproduces a displacement
In the case of gyroscopic effect, the planes of spin, gyroscopic couple and precession are
Which of the following is a lower pair?
Match List-I (measuring Devices) with List-IJ (Measuring parameter) and select the correct answer using the codes given below the lists
The following data pertain to a worker: base rate = Rs. 20 per hour
Time taken for completing the job =2 hours
Standard time = 3hours
Under Halsey plan the total earning of the worker is
What is the correct sequenceof the following parameters in order of their maximum to
minimum influence on toollife?
1. Feed rate
2. Depth of cut
3. Cutting speed
Select the correct answer using the codes given below
Given that cutting speed =9 m/min, the return time to cutting time ratio is = 1:2 the feed rate = 0.3 mm/stroke , the clearanceat each of cut = 25 mm and that the plate Is fixed 700 mm side along the direction of tool travel, the time required for finishing one flat surface of a plate of size 700 $$\times$$ 300 mm in a shaper, will be
The least count of a metric vernier caliper having 25 divisions on vernier scale , matching with 24 divisions of main scale (1 main scale divisions= 0.5 mm )is
Standards to be used for reference purposes in laboratories and workshops are termed as
For achieving a specific surface finish in single point turning the most important factor to be controlled is
Interchangeability can be achieved by
The centre and radius of the circle $$z\overline{z} - (2 + 3i)z - (2 - 3i)\overline{z} + 9 = 0$$ are
Enlarging an existing circular hole with rotating single point toolis called
Plug gauges are used to
Basic shaft and basic hole are those whose upper deviations and lower deviations respectively - are
The general equation of continuity for three-dimensional flow of a compressible fluid for steady flow is (where u, v, w are components of velocity in x, y and z directions respectively)
The density of air at $$10^\circ C$$ and 1MPa abs,in SI units is
In centrifugal pumps, maximum efficiency is obtained when the blades are
If the characteristics of a pump are as shown in fig. What is represented by abscissa
A rocket exists exhaust gases with $$\rho = 0.5 kg/m^3$$ out a 50 cm diameter nozzle at a velocity of 1200 m/s The thrust, is
Which of the following pairs of velocity components u and v satisfy the continuity equation for a two dimensional flow of an incompressible fluid?
The flow of a fluid in a pipe takes place from
An aeroplane is flying at an height of 14 km where temperature is $$-45^\circ C$$. The speed of the plane is corresponding to M = 2. Find the speed of the plane if R = 287 J/kg K and $$\gamma = 1.4$$.
Pipe 1, branches to three pipes as shown in the given figure. The areas and corresponding velocities are as given in the following table The value of $$V_2$$ in cm per second will be
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The pressure difference measured by a mercury oil differential manometer on the two sides of the orifice meter gives a reading of 50 cm of mercury. Determine the differential pressure head in orifice. Take the specific gravity ofoil as 0.9.
The transition Reynolds numberfor flow over flat plate is $$5 \times 10^5$$. What is the distance from the leading edge at which transition will occur for flow of water with a uniform velocity of 1m/s?(For water, the kinematic viscosity, $$v = 0.858 \times 10^{-6} m^2/s$$)
Pipes of lengths $$l_1, l_2$$ etc and diameter $$d_1, d_2$$, etc are connectedin series. A single pipe of length $$l_1 + l_2 + l_3 + ....$$ having same pressure loss as all pipes in series will have diameter equal to
Let x have the density function $$f(x) = \begin{cases}\frac{3}{4}(1 - x^2) & if -1 \leq x \leq 1\\0 & otherwise \end{cases}$$. Then the probability $$p\left(\frac{-1}{2} \leq x \leq \frac{1}{2}\right)$$ is
If thermal conductivity of a material varies as $$K_o(1 + \alpha T)$$, temperature at the center of a 10 cm thick wall of material will be
What is the net radiant interchange per square meter for two very large plates at temperatures 800 K and 500 K respectively? (The emissivity of the hot and cold plates are 0.8 and 0.6 respectively. Stefan Boltzmann constant is $$5.67^* 10^{-8} W/m^2 K^4$$).
A 10 kg solid at $$100^\circ C$$ with a specific heat, of 0.8kJ/kg. $$^\circ C$$ is immersed in 40 kg of $$20^\circ C$$ liquid with a specific heat of 4.0 kJ/kg $$^\circ C$$. Estimate the temperature after a long time if the container is insulated?
A spherical shaped vessel of 1.4 m outer diameter is 90 mm thick. Find the rate of heat leakage, if the temperature difference between the inner and outer surfaces is $$220^\circ C$$. Thermal conductivity of the material of the sphere is 0.083 W/m K.
$$\left(\frac{\partial p}{\partial V}\right)_T \left(\frac{\partial v}{\partial T}\right)_p \left(\frac{\partial T}{\partial p}\right)_v$$ is equal to
A well insulated vessel containing air is heated to double the pressure and temperature 150% in excess of initial. The amount of air that leaked is
An unconstraint thin circular disc has a concentric hole in it. On heating the diameter of the hole will
The specific heat of diatomic gas at constant pressure is given by (R = universal gas constant and M = molecular weight of gas)
The variation of temperature inside a wall is shown by three different curves. In which case thermal conductivity least varies with temperature
Kinetic energy of the molecules in terms of absolute temperature (T) is proportional to
Which type of heat exchanger an automobile radiator is?
Given that Nu = Nusselt number, Re = Reynoids number, Pr = Prandtl number, Sh = Sherwood number, Sc = Schmidt number and Gr = Grashoff number. The functional relationship for free convective heat transfer is given as,
The quantity of heat required to change the temperature of 1 gm of ice from $$—6^\circ C$$ to $$—5^\circ C$$ is known as
The spectral energy distribution for a body at temperature T is shown in figure. Now if the temperature of the body is increased
When K is the thermal conductivity, $$\tau$$ is the density and $$C_p$$, is the specific heat of a substance, then thermaldiffusivity is given by
The determinant of the matrix $$\begin{bmatrix}7 &0 & 0 & 0 \\9 & 3 & 0 & 0 \\4 & -6 & -2 & 0 \\0 & 0 & 0 & 1 \end{bmatrix}$$ is
A thin copper wire at $$300^\circ$$ is suddenly immersed in water at $$30^\circ C$$. It cools down to $$150^\circ C$$ in 70 seconds. It is then reheated to the initial temperature of $$300^\circ C$$ and suddenly exposedto air at $$30^\circ C$$ whereit cools down to $$150^\circ C$$ in 200 seconds. This difference in cooling time is due to
A heavy block of mass m is slowly placed on a conveyer belt moving with speed v. If coefficient of friction between block and the belt is $$\mu$$, the block will slide on the belt through distance
A car moving with speed u can be stopped in minimum distance x when brakes are applied. If the speed becomes n times, the minimum distance over which the car can be stopped would take the value
Speed of particle executing simple harmonic motion with amplitude a is half of the maximum speed. At that instant, displacement of the particle is
Two blocks with masses M and mare in contact with each other and are resting on a_ horizontal frictionless floor. When horizontal force is applied to the heavier, the blocks accelerate to the right. The force between the two blocks are
A stone of mass m at the end of a string of length | is whirled in a vertical circle at a constant speed. The tension in the string will be maximum when the stone is
Ratio of the radii of the planets $$P_1$$, and $$P_2$$, is k and ratio of the accelerations due to gravity on them is s. Ratio of escape velocities from them will be
Couple M is applied at C on a simply supported beam AB. The maximum shear on AC will be
A short column of external diameter D and internal diameter d, is subjected to a load W, with an eccentricity e, causing zero stress at an extremefiber. Then the value of ‘e’ must be
A beam AB is hinge-supported at its ends and is loaded by couple P.c. as shown in the figure. The magnitude of shearing force at a section x of the beam is
There are two bars of equal length and equal volume and same material, one having stepped diameters and other having uniform diameter. If maximum stress produced in both bars is
same, then stored energy will be
The given figure shows the shear force diagram for the beam ABCD. Bending moment in the portion BC of the beam
$$\sigma_x, \sigma_y$$ and $$\tau_{xy}$$ are the rectangular stress components at a point. The radius of Mohr’s circle is
For the case of a slender column oflength Land flexural rigidity EI built in at its base and free at the top, the Eulers critical buckling load is
When a beam is subjected to a transverse shearing force, the shear stress in the upper fibers will be
Angle made by $$2i - 3j + 4k$$ with the z-axis is
