Engineering Answers

27. A classroom that normally contains 40 people is to be air-conditioned with window air-conditioning units of 5 KW cooling capacity. A person at rest may be assumed to dissipate heat at a rate of about 360 KJ/hr. There are 10 light bulbs in the room, each with a rating of 100 watts. The rate of heat transfer to the classroom through the walls and the windows is estimated to be 15,000 KJ/hr. If the room air is to be maintained at a constant temperature of 21oC, determine the number of window air-conditioning units required.

26. An auditorium seating 1600 people is to be maintained at 80oF dry bulb and 65oF wet bulb temperature

when outdoor air is at 91oF dry bulb and 75oF wet bulb. Solar heat load is 120,000 Btu/hr and supply air is

at 60oF, determine the amount of supply air. (Use sensible heat load of 225 Btu/hr per person).

Dimension of susceptibility is

1/ Coulomb

Coulomb^2

It is dimensionless

None of the above

(1) Describe the composition of fabrication

(2) Describe the physical properties of fabrication

(3) Describe the mettods of fabrication

A vibration damper unit is composed of a rubber cylinder of diameter d compressed inside of a wrought-iron cylinder by a force F applied to the steel rod. Develop, in terms of d, F, and Poisson’s ratio ν for the rubber, the following expression for the lateral pressure p between the rubber and the wrought-iron cylinder.

Compute the value of 𝑝 for the following data: 𝑑 = 63.5 𝑚𝑚, 𝜈 =

0.5, 𝑎𝑛𝑑 𝐹 = 9 𝑘𝑁.

5. Compute for the enthalpy, internal energy, and entropy of steam at 72oC and 93%

quality.