A beam is fixed at one end and is vertically supported at the other end. What is the degree of statical indeterminacy?
ISRO Scientist or Engineer Mechanical May 2017
For the following questions answer them individually
In a gas turbine power plant, reheating of gases between high pressure and low pressure turbine stages will
The resultant of two forces acting at 60° is 7 N and when acting at right angles is $$\sqrt{34} N$$. The forces are
The metal removal rate in abrasive jet machining process is
The air inside a space capsule is maintained at the required condition by passing it through a set of heat exchangers. The heat exchangers are designed such that the humid air passing through them is cooled and partial condensation of the water vapour occurs. On a psychrometric chart, this process appears as a line which is
Two bolts A and B of same material and length are subjected to identical tensile load. If the elastic strain energy stored in bolt A is 16 times that of the bolt B and the mean
diameter of bolt A is 13 mm, the mean diameter of bolt B (in mm) is
The source of energy in ultrasonic machining process is
A turbine develops 500 kW power under a head of 100 m at 200 rpm. What would be its normal speed under a head of 81 m?
A solid rod of 12 mm diameter was tested for tensile strength with the gauge length of 50 mm. Final length = 80 mm; Final diameter = 4 mm; Yield load = 1130 N. What is the nearest yield stress and % reduction in area respectively?
When water at $$0^\circ C$$ is heated, its specific volume under standard atmosphere
A spherical joint has —————— degree (s) of freedom.
Isometric projection of a sphere is
ABC inventory control focuses on those
How does the viscosity of fluids vary with increase in temperature?
It is required to connect two parallel shafts, the distance between whose axes is small and variable. They can be coupled by
Under what condition does flow separation take place?
The variety of cast iron which has maximum hardness is
The Kutzback criterion for determining the number of degrees of freedom (n) of a mechanism with L as number of links, J as number of lower pairs and H as number of higher pairs is
The crystal structure of cementite is
Hardness will be highest after which of the following heat treatment process?
In which of the following type of gear train, the first gear and last gear are co-axial.
For heat transfer across a composite slab with materials having different thermal conductivity, study the following statements.
I. Temperature is continuous always.
II. Temperature gradient is not continuous.
III. Heat flow is not continuous.
Which of the following treatment does not improve hardness?
The ratio of the height of a porter governor (when the length of arms and links are equal) to the height of watt governor is: (m: mass of the ball; M : mass of the sleeve)
For a specified inlet and outlet temperatures, for which kind of heat exchanger will the log mean temperature difference, $$\triangle T_{lm}$$ will be highest?
Fatigue strength for non-ferrous materials is usually defined at —————— stress cycles.
If $$A = \begin{bmatrix}9 & 6 \\8 & 7 \end{bmatrix}$$ then $$det(A^{99} - A^{98})$$ is
$$\lim_{\theta \rightarrow \frac{\pi}{2}}\frac{\log \left(\theta - \frac{\pi}{2}\right)}{\tan \theta}$$ is
The solution of ODE $$y dx + x dy = 0$$ is
If $$\phi$$ is a scalar point function, the value of curl Grad $$\phi$$ is
The point where the plane x + 3y + 2z − 6 = 0 meets the line joining P (2, 1, 1) and Q (1, 3, − 2) is,
$$\int_{0}^{\frac{\pi}{2}}\sin^{7}x dx $$ is
Laplace transform of $$t \cos (at)$$ is
If two vectors $$\overrightarrow{a} = 3i + 4j - 7k$$ and $$\overrightarrow{b} = Pi - 6j + 3k$$ are perpendicular, the value of $$P$$ is
The arithmetic mean of 12 data point is 79. Later it was found that two data points were wrongly taken as 83 and 68 in place of 78 and 97. The actual mean is
How does cetane number varies with octane number in fuels in IC engines?
The relationship of the shear angle $$\phi = \frac{\pi}{4} - \beta + \frac{\alpha}{2}$$ is as per ('$$\alpha$$' is rake angle and '$$\beta$$' is friction angle)
For a plate with an elliptical hole subjected to tensile stress, $$\sigma$$ as shown in the figure, the maximum tensile stress at point P is
A centrifugal compressor is suitable for which of the following?
The optimum cutting speed for maximum production is (‘n’ is tool constant and ‘Tc ’ is time required to change the tool)
A rod of length L and area of cross section A has a modulus of elasticity E and coefficient of thermal expansion $$\alpha$$ . One end of the rod is fixed and other end is free. If the temperature of the rod is increased by $$\triangle T$$, then
The entropy of a hot baked potato decreases as it cools.
During January, at a location in Rohtang, winds at $$-6^\circ C$$ can be observed. Several meters below the ground, the temperature remains at $$27^\circ C$$. A scientist claims to have devised a power cycle exploiting this situation that has a thermal efficiency of 10%. Whether the claim is true?
The side relief angle in a cutting tool signature of 10, 20, 7, 6, 8, 15, 2 is
The missing distance between A and B in the pin figure shown below is
In an ideal gas turbine cycle with intercooling, reheating and regeneration as the number of compression and expansion states are increased, which of the following statements are correct?
I. The Brayton cycle reduces to Ericsson cycle.
II. The Brayton cycle reduces to Stirling cycle.
III. The cycle efficiency becomes equal to Carnot cycle efficiency.
Calculate the dynamic head ($$P_A - P_{static}$$) when a jet of water with a velocity, v strikes a flat plate moving with a velocity, u in the same direction as jet. (Take u = 4 m/s, v = 10 m/s and $$\rho = 1000 kg/m^3$$
The method of development of a right regular prism is
A light plane flies at 720 km/hr in standard air at an altitude of 1000 m. Determine the stagnation pressure at the leading edge of the wing. Take, $$P_{air} = 9.0 \times 10^4 N/m^2$$, $$\rho = 1.1 kg/m^3$$
Below the ductile to brittle transition temperature, weld joints show
What is the Prandtl number for a gas at $$27^\circ C$$ and $$1 \times 10^5$$ Pa, with with kinematic viscosity equal to $$1.8 \times 10^{-5} m^2/s$$, specific heat capacity at constant pressure = 700 J/kg-K and thermal conductivity of 0.02 W/m-K?(Take Gas constant = 300 J/kg-K)
In continuous casting process, the mould is generally made of
A re-entry module flies with Mach 10 at an ambient temperature of $$-27^\circ C$$ with $$C_P$$ = 840 J/kg-K, gas constant R = 140 J/kg-K. What is the stagnation temperature at the tip of the nose of the re-entry module?
Which one of the following steels contains least percentage of carbon?
The Lewis number which is a measure of relative thermal and concentration boundary layer thicknesses is defined as, (Re: Reynold’s number, Pr: Prandtl number, Sc: Schmidt number)
The figure shows an Aluminium rod of 25 mm$$^2$$ cross sectional area. It is loaded at four points, K, L, M and N. Assume E = 67 GPa for Aluminium. The total change in length of the rod due to loading as shown is close to
The basis of slip line field theory in metal cutting is
A room contains 25 kg. of air at 100 kPa and $$14^\circ C$$. The room has a 250 W refrigerator and 1 kW electric resistance heater. During a cold winter day, it is observed that both the refrigerator and the heater are running continuously, but the air temperature in the room remains constant. The rate of heat loss from the room during that day is
The bar AC, 10 m long supports a load of 6000 N as shown in figure. The cable BC is horizontal and 5m long. Forces in the cable and the bar are
In a grinding wheel specification of ‘wa36k8vbe’, “wa” indicates
Two Carnot heat engines are operating in series such that the heat sink of the first engine serves as the heat source of the second one. If the source temperature of the first engine is $$1327^\circ C$$, the sink temperature of the second engine is $$127^\circ C$$, and the thermal efficiency of both the engines are the same, the temperature of the intermediate reservoir is:
A body of mass 10 kg is initially stationary on a $$45^\circ$$ inclined plane as shown in figure. The coefficient of dynamic friction between the body and the plane is 0.3. The body slides down the plane and attains a velocity of 20 m/s. The distance travelled (in metre) by the body along the plane is close to
In metal forming, ring compression test is carried out to find out
Water flows into the top of an open drum at a constant mass flow rate. Water exits through a pipe near the base with a mass flow rate proportional to the height of the liquid. If the drum is initially empty, which of the following gives the plot of liquid height with time?
What is the approximate reaction moment at the fixed support A for the loaded frame shown below? (Take the diameter of the pulley as 250 mm)
A radiator on a space capsule must dissipate heat generated inside the capsule, by radiating it into space. While on the bright side of earth, the capsule sees the earth’s radiation and the solar radiation. The radiator surface has a solar absorptivity of 0.5 and an emissivity of 0.9. What is the maximum equilibrium surface temperature of the radiator, if the maximum heat generated in the capsule is 800 W/m$$^2$$? Assume earth’s radiation = 100 W/m$$^2$$ and solar irradiation = 524 W/m$$^2$$.
Take Stefan Boltzmann constant as $$5 \times 10^{-8} W/m^2-K^4$$
For profile controls, datum is
A simply supported beam of length L is subjected to a varying distributed load $$\sin \left(\frac{\pi x}{L}\right) N/m$$, where distance x is measured from the left support. The magnitude of the vertical reaction in N at the left support is
A packed bed of solid spheres acts as a thermal energy storage system. In a charging process, heat transfer from the hot gas increases thermal energy stored within the spheres. Consider two beds, one with aluminium spheres ($$\rho = 2700 kg/m^3$$, C = 950 J/kg-K, k = 240 W/m-K) and other with copper spheres ($$\rho = 8900 kg/m^3$$, C = 400 J/kg-K, k = 380 W/m-K). Select the correct graph for the temperature rise of a sphere at the inlet of the bed
Compressive residual stresses in weld joints
A force P is applied at a distance ‘ X ’ from the end of the beam as shown in the figure. What would be value of ‘ X ’ so that the displacement at ‘A’ is equal to zero?
An electric heater is sandwiched between two plates each 0.3 m long and 0.1 m wide with a thickness of 30 mm. At steady state condition the heater is maintained at a temperature of $$100^\circ C$$, with a current of 0.25 A and voltage of 200 V. Assume the plates are perfectly insulated at the edges, and the heater is having perfect contact with the plates to give a temperature of $$50^\circ C$$ on the outside of the plate surface. What is the thermal conductivity of the plate material?
Knife line or hairline cracking is observed in
Riser is designed so as to
A torque T is applied at the free end of a stepped rod of circular cross-sections as shown in the figure. The shear modulus of the material of the rod is G. The expression for diameter ‘d’ to produce an angular twist q at the free end is
A pin jointed uniform rigid rod of weight 981 N and length 1 m is kept horizontally by an external force F as shown in the figure below. The force F is removed suddenly. At the instant of force removal, the magnitude of vertical reaction (in N) developed at the support is close to
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The frictional torque transmitted in a conical pivot bearing considering uniform pressure is : (R: radius of shaft,a : semi angle of cone, $$\mu$$ : Coefficient of friction, W: load on bearing)
A mass of 2 kg is attached to two identical springs each with stiffness k = 40 kN/m as shown in the figure. Under friction less condition, the natural frequency of the system in Hz is close to
A rectangular steel plate is joined to a vertical post using four identical rivets arranged as shown below in the figure. The shear load on the worst loaded rivet (in N) approximately is
Match the following criterion of material failure under biaxial stresses $$\sigma_1$$ and $$\sigma_2$$ and yield stress $$\sigma_y$$ , with their corresponding graphic representations.
