Engineering Answers

A steady stream of air enters a horizontal compressor at the rate of 0.02 kg/s. The air temperature is 10o C at entry and 300o C at exit. The velocity of the air is 30 m/s at entry and 6 m/s at exit. During its passage through the compressor, the air experiences a heat loss of 105 kJ/kg of air. Calculate: (a) The change in kinetic energy per kg of air (b) The change in enthalpy per kg of air (c) The work done per kg of air (d) The power required to drive the compressor (e) The volume of air entering the compressor per second (f) The flow area of the entry pipe if the entry pressure is 1 bar Take R = 0.287 kJ/kgK and cp = 1.005 kJ/kgK

A +4% grade line intersects a -2 % grade line at station 6+800, where the elevation is 642.40 m. as shown in the figure. Determine the elevations of 100-m stations for this 1,000-m unequal tangent curve

In a Rankine cycle, what is the entrance pressure of the turbine if the condenser

pressure is 105 KPa and the pump work is 20 KJ/kg. Use density of water entering the

pump, 950 kg/m

Choose a quantity to be represented by a variable, then write a mathematical expression for each.

1. The product of three consecutive integers

2.. Jose's age in 10 years

3. The distance traveled by a man driving at the rate of 45 kph

4. The total amount in pesos of 30 coins consisting of 5-peso coins and 10-peso coins

5. The sum of three consecutive odd integers

6. The fraction of work done by a man who can finish a job in three days

7. The total interest after one year if a fraction of P500 000 is invested at 5% annual interest rate and the remaining part is invested at 7.5% annual interest rate

8. A three-digit number whose hundreds digit is twice its tens digit and the tens digit is 3 more than the units digit

9. The percentage of alcohol in a mixture formed by combining 1.5 liter of pure water and x liters of 30% alcohol solution.

10. The total distance traveled by a boat 1 hour and 20 minutes upstream and 40 minutes downstream if the rate of the current is 3 kph.

2.) An asset costing P50,000 has a life expectancy of 6 years and an estimated salvage value of P8,000. Calculate the depreciation charge at the end of the fourth period using fixed-percentage method.

A construction company has an opportunity to submit a bid for the construction of a new apartment building. From the specification provided by the developer, the PERT network along with the three time estimate (in week) for each activity as shown in figure-1.