In a simple Brayton cycle, the pressure ratio is 8 and temperatures at the entrance of compressor and turbine are 300 K and 1400 K,respectively.
Both compressor and gas turbine have isentropic efficiencies equal to 0.8. For the gas, assume a constant value of cp (specific heat at constant pressure) equal to 1 kJ/kgK and ratio of specific heats as 1.4. Neglect changes in kinetic and potentialenergies.
The power required by the compressor in kW/kg of gas flow rate is
In orthogonal turning of a bar of 100 mm diameter with a feed of 0.25 mm/rev, depth of cut of 4 mm and cutting velocity of 90 m/min, it is observed that the main (tangential) cutting force is perpendicular to the friction force acting at the chip-toolinterface.
The main (tangential) cutting force is 1500 N. The normal force acting at the chip-tool interface in N is
The solution to the differential equation d2u/dx2 - k du/dx = 0 where k is a constant, subjected to the boundary conditions u(0) = 0 and u(L) = U, is
u = U[(1 - ekx)/(1 - ekL)]
u = U[(1 + ekx)/(1 + ekL)]
u = U x/L
u = U[(1 - e-kx)/(1 - e-kL)]
The probability that a student knows the correct answer to a multiple choice question is 2/3. If the student does not know the answer, then the student guesses theanswer.
The probability of the guessed answer being correct is 1/4. Given that the student has answered the question correctly, the conditional probability that the student knows the correct answer is
Two large diffuse gray parallel plates, separated by a small distance, have surface temperatures of 400 K and 300 K. If the emissivities of the surfaces are 0.8 and the Stefan-Boltzmann constant is 5.67 * 10-8W/m2K4, the net radiation heat exchange rate in kW/m2 between the two plates is
A simply supported beam of length L is subjected to a varying distributed load sin
(3 π x/L) Nm-1, where the distance x is measured from the leftsupport.
The magnitude of the vertical reaction force in N at the left support is
A single degree of freedom system having mass 1 kg and stiffness 10 kN/m initially at rest is subjected to an impulse force of magnitude 5 kN for 10-4seconds.
The amplitude in mm of the resulting free vibration is
Cylindrical pins of mm diameter are electroplated in ashop.
Thickness of the plating is 30±2.0micron.
Neglecting gage tolerances, the size of the GO gage in mm to inspect the plated components is
The following surface integral is to be evaluated over a sphere for the given steady velocity vector field F = xi + yj + zk defined with respect to a Cartesian coordinate system having i, j and k as unit basevectors.
where S is the sphere x2 + y2 + z2 = 1 and n is the outward unit normal vector to thesphere.
The value of the surface integral is
Consider one-dimensional steady state heat conduction along x-axis(0 ≤ x ≤ L) through a plane wall with the boundary surfaces (x=0 and x=L) maintained at temperatures of 0°C and 100°C. Heat is generated uniformly throughout thewall.
Choose the CORRECT statement
The temperature distribution is linear within the wall.
The direction of heat transfer will be from the surface at 100°C to the surface at 0°C.
The temperature distribution is symmetric about the mid-plane of the wall.
The maximum temperature inside the wall must be greater than 100°C.
In order to have maximum power from a Pelton turbine, the bucket speed must be
independent of the jet speed.
equal to the jet speed.
equal to twice the jet speed.
equal to half of the jet speed.
Customers arrive at a ticket counter at a rate of 50 per hr and tickets are issued in the order of theirarrival.
The average time taken for issuing a ticket is 1min.
Assuming that customer arrivals form a Poisson process and service times are exponentially distributed, the average waiting time in queue in min is
Match the CORRECT pairs
P-2, Q-1, R-3
P-3, Q-1, R-2
P-3, Q-2, R-1
P-1, Q-2, R-3
The eigenvalues of a symmetric matrix are all
complex with non-zero positive imaginary part.
complex with non-zero negative imaginary part.
The partial differential equation is a
linear equation of order 2
linear equation of order 1
non-linear equation of order 2
non-linear equation of order 1
For a particular project, eight activities are to be carriedout.
Their relationships with other activities and expected durations are mentioned in the tablebelow.
If the duration of activity f alone is changed from 9 to 10 days, then the
critical path changes and the total duration to complete the project changes to 17 days.
critical path remains the same and the total duration to complete the project changes to 19 days.
critical path and the total duration to complete the project remain the same.
critical path changes but the total duration to complete the project remains the same.
Air enters an adiabatic nozzle at 300 kPa, 500 K with a velocity of 10 m/s. It leaves the nozzle at 100 kPa with a velocity of 180 m/s. The inlet area is 80cm2.
The specific heat of air Cp is 1008 J/kg.K.The exit area of the nozzle in cm2 is
A refrigerator operates between 120 kPa and 800 kPa in an ideal vapor compression cycle with R-134a as therefrigerant.
The refrigerant enters the compressor as saturated vapor and leaves the condenser as saturatedliquid.
The mass flow rate of the refrigerant is 0.2 kg/s. Properties for R-134a are as follows:The rate at which heat is extracted, in kJ/s from the refrigerated space is
In a single pass rolling process using 410 mm diameter steel rollers, a strip of width 140 mm and thickness 8 mm undergoes 10 % reduction ofthickness.
The angle of bite in radians is
The state of stress at a point under plane stress condition is σxx = 40 MPa, σyy = 100 MPa and τxy = 40MPa.
The radius of the Mohr’s circle representing the given state of stress in MPa is
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