Mechanical Engineering Answers

Air enters a compressor with a stagnation pressure of 100 kPa and a stagnation

temperature of 27°C, and it is compressed to a stagnation pressure of 900 kPa.

Assuming the compression process to be isentropic, determine the power input to the

compressor for a mass flow rate of 0.02 kg/s.

A cylinder of volume 0.5m³ of steam at 4 bar and 200⁰c.if the steam is cooled at constant pressure until the volume become 0.1m³,find the mass of the steam and calculate the final dryness of fraction, work done and heat transfer

A cylinder that contains 0.067 kg of carbon dioxide (with molar mass 44 kg/kmol), occupying a volume of 0.022 m3 at 1.0 bar is compressed reversibly until the pressure is 7.20 bar. If the molar (universal) gas constant as 8.3145 kJ/kmol K, calculate the the work done on the C02 (in J) when the process is isothermal.

A 20-kg mass of iron at 100°C is brought into contact with 20 kg of aluminum at 200°C in

an insulated enclosure. Determine the final equilibrium temperature of the combined system. 

a reversible heat engine absorbs 1000 kilo cal of heat at 327 degree Celsius and produces a work and discards heat at 29 degree Celsius what is the change in entropy of heat source and heat sink what is the total entropy change results from the process

A spring-mass system, with m = 100 kg and k = 400 N/m, is subjected to a harmonic force

f(t)= F0 cos (wt) with F0 = 10 N. Find the response of the system when v is equal to (a) 2

rad/s, (b) 0.2 rad/s, and (c) 20 rad/s.

As shown below in the figure, a bracket with a solid circular cross-section of radius r = 67 mm is inserted into a frictionless sleeve (slightly larger than the bracket) at A and is also supported by a pin at C. The sleeve at A allows free rotation of the bracket with respect to z_o axis and also freely translate about the same axis. The bracket has two arms, namely arm AB of length b = 0.75 m and arm BC of length a = 0.40 m. Moments M₁ = 1.6 kN.m and M₂=1.91 kN.m are applied at the point C.

1. calculate the maximum tensile stress along with the location and direction.

2. calculate the maximum compressive stress along with the location and direction.

3. calculate at point p(see cross section and the figure) on the cross-section at A the maximum in-plane shear stress.

4. also identify the point where absolute maximum shear stress takes place and calculate the same with the direction.

A single-threaded worm has an axial pitch of 20 mm and a pitch diameter of 50 mm. The worm rotates at 500 rev/min and drives a gear having 40 teeth and a transverse pressure angle. The power transmitted is 0.5 kW. Determine (a) the lead angle of the worm, (b) the center distance between worm and gear, and (c) the tangential, radial, and thrust forces on the worm gear.

(a)  Air at 2.01 bar, 27° C, initially occupying a volume of 0.015 m³, is compressed reversibly and adiabatically by a piston to a pressure of 6.8 bar. Calculate:

(i)                The final temperature                                                                       (6 marks)

(ii)             The final volume                                                                              (4 marks)

(iii)           The work done on the mass of air                                                (5 marks)