Q. The true stress (in MPa) versus true strain relationship for a metal is given by σ = 1020e 0.4  The cross-sectional area at the start of a test (when the stress and strain values are equal to zero) is 100 mm2. The cross-sectional area at the time of necking (in mm2) is ...

Q. A test is conducted on a one-fifth scale model of a Francis turbine under a head of 2 m and volumetric flow rate of 1 m3/s at 450 rpm. Take the water density and the acceleration due to gravity as 103 kg/m3 and 10 m/s2, respectively. Assume no losses both in model and prototype turbines. The ...

Q. Ambient air is at a pressure of 100 kPa, dry bulb temperature of 30 oC and 60% relative humidity. The saturation pressure of water at 30 oC is 4.24 kPa. The specific humidity of air (in g/kg of dry air) is_______(correct to two decimal places). Ans: 16.00 - 16.50

Q. A standard vapor compression refrigeration cycle operating with a condensing temperature of 35oC and an evaporating temperature of -10 oC develops 15 kW of cooling. The p-h diagram shows the enthalpies at various states. If the isentropic efficiency of the compressor is 0.75, the magnitude of ...

Q. Air is held inside a non-insulated cylinder using a piston (mass M=25 kg and area A=100 cm2) and stoppers (of negligible area), as shown in the figure. The initial pressure Pi and temperature Ti of air inside the cylinder are 200 kPa and 400°C, respectively. The ambient pressure P¥ and ...

Q. A 0.2 m thick infinite black plate having a thermal conductivity of 3.96 W/m-K is exposed to two infinite black surfaces at 300 K and 400 K as shown in the figure. At steady state, the surface temperature of the plate facing the cold side is 350 K. The value of Stefan- Boltzmann constant, s, is ...

Q. A frictionless circular piston of area 10-2 m2 and mass 100 kg sinks into a cylindrical container of the same area filled with water of density 1000 kg/m3 as shown in the figure. The container has a hole of area 10-3 m2 at the bottom that is open to the atmosphere. Assuming there is no leakage ...

Q. A force of 100 N is applied to the centre of a circular disc, of mass 10 kg and radius 1 m, resting on a floor as shown in the figure. If the disc rolls without slipping on the floor, the linear acceleration (in m/s2) of the centre of the disc is _________(correct to two decimal places). ...

Q. A bar is subjected to a combination of a steady load of 60 kN and a load fluctuating between -10 kN and 90 kN.   The   corrected   endurance   limit   of   the   bar   is 150 MPa, the yield strength of the material is 480 MPa and the ultimate strength of the material is 600 MPa. The bar ...

Q. A thin-walled cylindrical can with rigid end caps has a mean radius R = 100 mm and a wall thickness of t = 5 mm. The can is pressurized and an additional tensile stress of 50 MPa is imposed along the axial direction as shown in the figure. Assume that the state of stress in the wall is uniform ...

Q. Air flows at the rate of 1.5 m3/s through a horizontal pipe with a gradually reducing cross- section as shown in the figure. The two cross-sections of the pipe have diameters of 400 mm and 200 mm. Take the air density as 1.2 kg/m3 and assume inviscid incompressible flow. The change in pressure ...

Q. A bimetallic cylindrical bar of cross sectional area 1 m2 is made by bonding Steel (Young’s modulus = 210 GPa) and Aluminium (Young’s modulus = 70 GPa) as shown in the figure. To maintain tensile axial strain of magnitude 10-6 in Steel bar and compressive axial strain of magnitude 10-6 in ...