Mechanical Engineering Answers

During an isentropic process of 2 kg_m/sec of oxygen, the temperature increases from 20°C to 120°C. Calculate ▲H, ▲W, Q, ▲S, ⌠pdv and -⌠vdp.

There are 1.5 Kg_m of a gas where K = 1.3 and R = 0.38 KJ/Kg_m - °R that undergo an isochoric process from p₁ = 0.552 MPa, t₁ = 58.5°C top₂ = 1.66 MPa. During the process, there added 100 KJ of heat. Compute the heat transferred, change of internal energy and the change of entropy.

Air with c_v = 0.723 KJ/Kg_m - °R is compressed in a piston-cylinder machine according to pV^1.3 = c from an initial temperature of 17°C and pressure of 1 bar, to a final pressure of 5 bars. Determine the final temperature, the heat transferred and the work.

Ammola vapor is compressed in a closed system from 15 psia, 3 cu ft, to 150 psia, 0.4 cu ft. according to the relation pVⁿ = constant. Assumin the vapor to be an ideal gas with the gas constant as 90.72 lb_m-ft/lb_f -°R and c_v = 0.384 BTU/lb_m - °R compute the heat transferred and the work.

One pound of air R = (53.3 ft-lb_f/lb_m-°R) is compressed isothermally in a closed system from 15 psia and 80°F to 90 psia. Compute the heat transfer.

Task 2

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Compare and contrast the use of D’Alembert’s principle with the principle of conservation of energy to solve an engineering problem

A motor vehicle having a mass of 800 kg is at rest on an incline of 1 in 8 when the brakes are released. The vehicle travels 30 m down the incline against a constant frictional resistance to motion of 100 N where it reaches the bottom of the slope.

a) Using the principle of conservation of energy, calculate the velocity of the vehicle at the bottom of the incline.

b) Using an alternative method that does not involve a consideration of energy, cauсate the velocity of the vehicle at the bottom of the incline.

c) Discuss the merits of the two methods you have used for parts a) and b) of this question. Justify the use of an energy method for these types of problems.

step by step

Task 2 – Compare and contrast the use of D’Alembert’s principle with the principle of conservation of energy to solve an engineering problem A motor vehicle having a mass of 800 kg is at rest on an incline of 1 in 8 when the brakes are released. The vehicle travels 30 m down the incline against a constant frictional resistance to motion of 100 N where it reaches the bottom of the slope. a) Using the principle of conservation of energy, calculate the velocity of the vehicle at the bottom of the incline. b) Using an alternative method that does not involve a consideration of energy, cacluate the velocity of the vehicle at the bottom of the incline. c) Discuss the merits of the two methods you have used for parts a) and b) of this question. Justify the use of an energy method for these types of problems.

Step by Steps

Task 2 – Compare and contrast the use of D’Alembert’s principle with the principle of conservation of energy to solve an engineering problem A motor vehicle having a mass of 800 kg is at rest on an incline of 1 in 8 when the brakes are released. The vehicle travels 30 m down the incline against a constant frictional resistance to motion of 100 N where it reaches the bottom of the slope. a) Using the principle of conservation of energy, calculate the velocity of the vehicle at the bottom of the incline. b) Using an alternative method that does not involve a consideration of energy, cacluate the velocity of the vehicle at the bottom of the incline. c) Discuss the merits of the two methods you have used for parts a) and b) of this question. Justify the use of an energy method for these types of problems.

Task 2 – Compare and contrast the use of D’Alembert’s principle with the principle of conservation of energy to solve an engineering problem A motor vehicle having a mass of 800 kg is at rest on an incline of 1 in 8 when the brakes are released. The vehicle travels 30 m down the incline against a constant frictional resistance to motion of 100 N where it reaches the bottom of the slope. a) Using the principle of conservation of energy, calculate the velocity of the vehicle at the bottom of the incline. b) Using an alternative method that does not involve a consideration of energy, cacluate the velocity of the vehicle at the bottom of the incline. c) Discuss the merits of the two methods you have used for parts a) and b) of this question. Justify the use of an energy method for these types of problems.

A reciprocating compressor draws in 14.17 cubic meter per minute of air whose density is 1.26 kg/cu meter and discharges it with a density of 4.86 kg/cu meter at the suction, p1 = 103.42 kPaa; at discharge, p2 = 551.58 kPaa. The increase in the specific internal energy is 78.6188 KJ/kg and the heat transferred from the air by cooling is 30.238 KJ/kg., determine the work on the air in KJ/min. Neglect change in kinetic energy.