Mechanical Engineering Answers

The temperature in a vessel is 36 degree C and the proportion by mass of
air to dry saturated steam is 0.1. What is the pressure in the vessel in bar
and in mm of mercury vacuum? The barometric pressure is 760mm Hg?

In an air compressor the pressures at inlet and outlet are 1bar and 5bar respectively. The temperature of the air at inlet is 15 degree C and the volume at the beginning of compression is three times that at the end of compression. Calculate the temperature of the air at outlet and the increase of internal energy per kg of air.

manufacturing is a basic subject which related to basic need of people as well as standard of a country discuss why it is necessary for all engineers to know about manufactruing processes

Lubricating oil enters the tubes of a heat exchanger at 74C and leaves at 34 C. The diameter of the tube is 50 mm and the oil flow through the tube at 2.5 m/s.
Input power to the system is 30 kW.
The specific heat capacity of the oil is 2.28 kJ/kgK and the density is 900 kg/m3. Determine;
a. The mass flow rate of the oil.
b. The thermal efficiency of this heat transfer process.

For a reversed heat engine the evaporator and condenser temperature at -5 and 50 degree Celsius respectively. The specific heat capacity at constant pressure is 0.956kJ/KgK if the mass flow rate of the refrigerant is 0.012kg determine the evaporator heat loads, C.O.P Of the refrigerator and heat pump and power

A compressed air storage cylinder has a volume of 1 m3 and contains air at an absolute pressure of 2 MPa and temperature 25°C. A quantity of the air is released during which the temperature of the remaining air falls to 15°C and the pressure to 1 MPa. The characteristic gas constant for air is 287 Jkg−1K−1.

Calculate the mass of the air released.

A pile driver hammer of mass 272 kg falls freely through a distance of 4.2 m to strike a pile of mass 516 kg and drives it 75 mm into the ground. The hammer does not rebound when driving the pile. Determine the average resistance of the ground. (Use D’Alembert’s principle and compare the principle of Conservation of Energy when solving the problem).

A pile driver hammer of mass 272 kg falls freely through a distance of 4.2 m to strike a pile of
mass 516 kg and drives it 75 mm into the ground. The hammer does not rebound when driving the pile. Determine the average resistance of the ground.

Note: You must fully answer each task and show all steps, including text. You must include
labelled diagrams to aid your solutions.

A lift cage of mass 826 kg accelerates uniformly upwards from rest to a velocity of 7 ms−1
whilst travelling a distance of 36 m. The frictional resistance to motion is 244 N. Making
use of the principle of conservation of energy, determine:

i) The work done
ii) The tension in the lifting cable
Iii) The average power developed

A space vehicle travelling at a velocity of 1206ms−1 separates by a controlled explosion
into two sections of mass 952 kg and 332 kg. The two parts carry on in the same direction
with the lighter front section moving 145 ms−1 faster than the heavier rear section. Determine the
final velocity of each section. Ensure you include a labelled diagram.