Engineering Answers

5. Compute for the enthalpy, internal energy, and entropy of steam at 72oC and 93% quality. Please explain the answer?

The specific heat at constant pressure of 1kg fluid undergoing a non –flow constant pressure

process is given by:

𝐶𝑝 = [2.5 +

40

𝑇+20]kJ/kg-℃ where T is in degrees centigrade. The pressure during the process

is maintained at 2 bar and volume changes from 1m3

to 1.8 m3

and temperature changes from

50℃ to 450℃. Determine (a) heat added (b) work done (c) change in internal energy (d) change

in enthalpy

Discuss four alternatives that increase the use and application of conventional concrete

Discuss the creep response of concrete structures. Provide examples of the effect of creep on concrete structures.

Discuss the change in volume of concrete at early ages

Discuss five different methods of concrete curing

Perfect Gases

0.675kg of gas at 1.4 MN/m² and 280⁰C is expanded to four times the original volume according to the law PV^1.3 =C Determine:

(a) the original and final volume of the gas,

(b) the final pressure of the gas

(c) the final temperature of the gas

Take R=0.287Kj/kg K

0.1m³ of gas is compressed from pressure of 120KN/m² and temperature 25⁰C to a pressure of 1.2MN/m² according to the law PV^1.2 = constant.

Determine,

(a) The work transferred during the compression,

(b) The change in internal energy,

(c) The heat transferred during the compression

Assume , c_v=0.72kJ/kgK         and           R=0.285KJ/kgK

Two equal 5-module, 20 degree gears mesh

together such that the addendum circle of each

gear passes through the interference point of the

other. If the contact ratio is 1.622, calculate the

number of teeth and the outside radius on each

gear.

Create an illustration of a series circuit that connects a battery and five capacitors and with a total capacitance of 3/7 F. The total charge in the circuit must be 2/9 C.