Mechanical Engineering Answers

When a certain perfect gas is heated at constant pressure from 15 oC to 95 oC, the

heat required is 1136 kJ. While when the same gas is heated at constant volume

between the same temperature limit above the heat required is 808 kJ. Calculate

cp,cv,



, R and molecular weight of the gas.

Air at 200kPa, 30°C is contained in a cylinder behind a piston with initial volume of 0.1 m3. The inside pressure balance ambient pressure of 100 kPa plus an external imposed force that proportional to V3, Now heat is transfer to the systēm to final pressure of 225 kPa. Find the work done for this process

A short reinforced concrete column of section 200 mm x 220mm is to be reinforced with 4 numbered steel bars and is required to carru an axial load of 850kN. The stress in the concrete must not exceed 7N/mm^2 and the stress must not exceed 150N/mm^2. Determine the diameter required for the bars and the subsequent stresses occurring in the concrete and the steel under the specified load. (Young's moduli of concrete=14kN/mm^2 and Young's moduli of steel=210kN/mm^2. With suitable sketch

A container (with a movable piston) contains 20.0 L of compressed nitrogen gas at 10.0 bar and 25.0 oC. Calculate q, w, ∆ U and ∆H as one lets the gas expand reversibly and isothermally to a pressure of 1.00 bar.

A student is sitting in the sun reading the exam. He has brought with him a bottle of 1.00 L of water. After 2 hours the temperature of the water has increased from 4 ° C to 20 ° C. During these two hours the sun / surroundings have supplied the water -66.90 kJ. Assume that the volume of 1.00 kg of water is 1.00 L and calculate the heat capacity of the water.

To a closed system, 150kJ of work is supplied. If the initial volume is 1.6m^3 and the pressure of the system changes as P=(8+4v) P in bar and v in m^3, determine the fluid volume and pressure of the system

Problem 3 You are building a replica of Stonehenge and need to move the Sarsen stones. The stones each weigh 350 kN. There are always at least 4 logs under the stone. The total width of the sleds supported on each stone is 750mm. The modulus of elasticity for the logs is 14.9 GPa and Poisson's ratio 0.033

If the maximum contact stress allowed on a log is 70 MPa, what is the minimum diameter for the logs?

A hydrostatic bearing is used to rotate a load. The load 500kN, fluid viscosity 500 mPa-s. The bearing has an outside diameter of 500mm and an inside diameter of 400mm.

a) What flow Q is required if the film thickness is 1mm?
b) What Pressure is required?
c) what is the friction torque if it is rotated at 3 rad/s?

The displacement of the GX160 engine cylinder is 160 cm^3. Assuming the engine is running at a constant speed of 1200 rpm (revolutions per minute), and that the choke and throttle valve are fully open, what would the intake air flow rate into the engine cylinder be, in l/min (litres per minute) [Hint: The engine speed is the crankshaft rotation speed. Think about the 4-stroke cycle and crankshaft/camshaft sprocket diameter ratio]?

How many times per combustion cycle is each valve opened?