1. Chapter 1 INTRODUCTION AND BASIC CONCEPTS Thermodynamics 1- 1C Classical thermodynamics is based on experimental. Home · Documents; Termodinamica – 5ta Edicin -Yunus a. Cengel & Michael a. Boles. LIBROS UNIVERISTARIOS Y Approach Seventh Edition Yunus A. Cengel, Michael A. Boles McGraw-Hill, Analysis The mass of the air in the room is ROOM 3 3 AIR m = ρV = ( kg/m)(6 × 6 × 8.

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Post on Nov views. There is no creation of energy, and thus no violation of the conservation of energy principle. It violates the second law of thermodynamics.

Therefore, this cannot tremodinamica. Using a level meter a device with an air bubble between two marks of a horizontal water tube it can shown that the road that looks uphill to the eye is actually downhill. Mass, Oibro, and Units C Pound-mass lbm is the mass unit in English system whereas pound-force lbf is the force unit.

One pound-force is the force required to accelerate a mass of In other words, the weight of a 1-lbm mass at sea level is 1 lbf. The light-year unit is then the product of a ed and time. Hence, this product forms a distance dimension and unit. Limited distribution permitted only to teachers and educators for course preparation.

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## Termodinámica – Yunus A. Cengel, Michael A. Boles – 7ma Edición

His weight on the moon is to terodinamica determined. Analysis Applying Newton’s second law to the weight force gives lbm4. Then, his weight on the moon will be lbf The mass and weight of the air in the room are to be determined. Assumptions The density of air is constant throughout the room. Its weight is to be determined. Analysis Applying Newton’s second law, the weight is determined to be lbf9.

The net upward force acting on a man in the aircraft is to be determined. The acceleration of the rock is to be determined. Analysis The weight of the rock is N The entire EES solution is to be printed out, including the numerical results with proper units. Cegel The problem is solved using EES, and the solution is given below. The percent reduction in the weight of an airplane cruising at 13, m is to be determined.

Properties The gravitational acceleration g is given to be 9.

### Termodinamica – 5ta Edicin -Yunus a. Cengel & Michael a. Boles

Analysis Weight is proportional to the gravitational acceleration g, and thus the percent reduction in weight is equivalent to the percent reduction in the gravitational acceleration, which is determined from 0. Discussion Note that the weight loss at cruising altitudes is negligible.

The system can also interact with the surroundings by exchanging heat and work across its control boundary. By tracking these interactions, we can determine the energy conversion characteristics of this system. This system cengle a closed or fixed mass system since no mass enters or leaves it.

Any system selected for this analysis must include the fuel and air while it is undergoing combustion. The volume that contains this air- fuel mixture within piston-cylinder device can be used for this purpose. One can also place the entire engine in a control boundary and trace the system-surroundings interactions to determine the rate at which the engine generates carbon dioxide.

This includes all streams entering or leaving the lake, any rain falling on the lake, any water evaporated to the air tfrmodinamica the lake, any seepage to the underground earth, and any springs that may be feeding water to the lake. Hence, specific weight is an intensive property. If we divide a system into smaller exicion, each portion will contain fewer termodinamoca particles than the original system.

The number of moles is therefore an extensive property. However, there should be no unbalanced pressure forces present. The increasing pressure with depth in a fluid, for example, should be balanced by increasing weight. Many engineering processes can be approximated as being quasi-equilibrium.

The work output of a device is maximum and the work input to a device is minimum when quasi-equilibrium processes are used instead of nonquasi-equilibrium processes. Pressure, temperature, and water content i.

But, other properties like wind speed and chemical composition i. Assuming that the air composition and velocity do not change and that no pressure front motion occurs during the day, the warming process is one of constant pressure i.

A relation for the variation of density with elevation is to be obtained, the density at 7 km elevation is to be calculated, and the mass of the atmosphere using the correlation is to be estimated. Assumptions 1 Atmospheric air behaves as an ideal gas. Properties The density data are given in tabular form as 0 5 10 15 20 25 0 0.

EES Solution for final result: The operation of these two thermometers is based on the thermal expansion of a fluid. If the thermal expansion coefficients of both fluids vary linearly with temperature, then both fluids will expand at the same rate with temperature, and both thermometers will always give identical readings. Otherwise, the two readings may deviate. It is to be expressed in K. It is to be expressed in F, K, and R. Analysis This problem deals with temperature changes, which are identical in Kelvin and Celsius scales.

Analysis Using the conversion relations between the various temperature scales, F Analysis Using the conversion relation between the temperature scales, C Analysis The lower and upper limits of comfort range in C are C For a constant volume of blood to be discharged by the heart, the blood pressure must increase to overcome the increased resistance to flow.

It is the gage pressure that doubles when the depth is doubled. This is a consequence of the pressure in a fluid remaining constant in the horizontal direction. An example of Pascals principle is the operation of the hydraulic car jack. It is to be converted to SI units. Assumptions The listed pressure is gage pressure. The tank’s pressure in various units are to be determined.

Analysis Using the kPa to psia units conversion factor, psia This is to be expressed in psia unit. Properties The density of water is taken to be Analysis Applying the hydrostatic equation, psia1. Analysis Using the mm Hg to kPa units conversion factor, kPa The gage pressure of air in the tank is to be determined.

Assumptions The air pressure in the tank is uniform i. The atmospheric pressure is to be determined. Analysis The atmospheric pressure is determined directly from kPa The gage pressure in the same liquid at a different depth is to be determined.

Assumptions The variation of the density of the liquid with depth is negligible. The local atmospheric pressure and the absolute pressure at the same depth in a different liquid are to be determined.

Assumptions The liquid and water are incompressible. Analysis The area upon which pressure 1 acts is 2 22 1 1 in The minimum imprint area per shoe needed to enable her to walk on the snow without sinking is to be determined. Assumptions 1 The weight of the person is distributed uniformly on the imprint area of the shoes. Analysis The mass of the woman is given to be 70 kg.

For a pressure of 0. Therefore, some sinking of the snow should be allowed to have shoes of reasonable size.

The absolute pressure in the tank is to be determined. Analysis The atmospheric or barometric pressure can be expressed as Pabs edicioh psi psia The vertical distance climbed is to be determined. Analysis Taking an air column between the top and the bottom of the mountain and writing a force balance per unit base area, we obtain bar0. The height of the building is to be determined. Assumptions The variation of air density with altitude is negligible.

Analysis Atmospheric pressures at the top and at the bottom of the building are kPa Delta P due to the air fluid column height, h, between the top and bottom of the building.

The pressure exerted on the surface of the diver by water is to be determined. Assumptions The variation of the density of water with depth is negligible.

The pressure of the gas is to be determined.

## Termodinamica – 5ta Edicin -Yunus a. Cengel & Michael a. Boles

The effect of the spring force in the range of 0 to N on the pressure inside the cylinder is to be investigated. The pressure against the spring force is to be plotted, and results are to be discussed. For a specified reading of gage pressure, the difference between the fluid levels of the two arms of the manometer is to be determined for mercury and water.

Differential fluid height against the density is to be plotted, and the cengell are ynuus be discussed.