# If the built-up beam is subjected to an internal moment of 75 kn\sdot m, determine the maximum...

## Question:

Liquid H{eq}_2{/eq}O at 20{eq}^o{/eq}C is contained in an insulated piston cylinder device isolated from a separate 6 kg of H{eq}_2{/eq}O vapor at 1 bar and 200{eq}^o{/eq}C. Notice the liquid volume is less than 0.1 m{eq}^3{/eq}, so negligible compared to the initial vapor volume (13 m{eq}^3{/eq}). Then the 2 masses come into thermal contact causing all the vapor to condense into liquid. The total final volume is also negligibly small. The pressure remains constant at 100 kPa throughout the process so the system work 1W{eq}_2{/eq} = p(V{eq}_2{/eq} - V{eq}_1{/eq}) = -1300 kJ. The final temperature is 70{eq}^o{/eq}C. Mass & energy equation to solve. The initial mass of the liquid H{eq}_2{/eq}O (to the nearest integer value in kg) is approximately.

## THERMAL CONTACT

In heat transfer and thermodynamics, a thermodynamic system is said to be in thermal contact with another system if it can exchange energy through the process of heat.The study of heat conduction between such bodies is called thermal contact conductance (Or thermal contact resistance).

## ENTHALPY

Enthalpy is a thermodynamic property of a system. It is the sum of the internal energy added to the product of the pressure and volume of the system. It reflects the capacity to do non-mechanical work and the capacity to release heat.

Enthalpy is denoted as H; specific enthalpy denoted as h. Common units used to express enthalpy are the joule, calorie, or BTU (British Thermal Unit.) Enthalpy in a throttling process is constant.

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{eq}\text{Let the liquid mass of }H_2O=m\\ T_{initial}=20^\circ C\\ T_{final}=70^\circ C\\ \text{Heat lost by vapour}=m(h_{200^\circ... 