1. a glass window of width w = 1 m and height h = 2 m is 5 mm thick and has a thermal conductivity of kg = 1.4 w/m*k. if the inner and outer surface temperatures of the glass are 15°c and -20°c. respectively, on a cold winter day, what is the rate of heat loss through the glass?
2. to reduce heat loss through windows, it is customary to use a double pane construction in which adjoining panes are separated by an air space. if the spacing is 10 mm and the glass surfaces in contact with the air have temperatures of 10° c and - 15°c, what is the rate of heat loss from a 1 m times 2 m window? the thermal conductivity of air is ka = 0.024 w/m*k.

Amass of m 1.5 kg of steam is contained in a closed rigid container. initially the pressure and temperature of the steam are: p 1.5 mpa and t 240°c (superheated state), respectively. then the temperature drops to t2= 100°c as the result of heat transfer to the surroundings. determine: a) quality of the steam at the end of the process, b) heat transfer with the surroundings. for: p1.5 mpa and t 240°c: enthalpy of superheated vapour is 2900 kj/kg, specific volume of superheated vapour is 0. 1483 m/kg, while for t 100°c: enthalpy of saturated liquid water is 419kj/kg, specific volume of saturated liquid water is 0.001043m/kg, enthalpy of saturated vapour is 2676 kj/kg, specific volume of saturated vapour is 1.672 m/kg and pressure is 0.1 mpa.

The thermal expansion or contraction of a given metal is a function of the f a)-density b)-initial temperature c)- temperature difference d)- linear coefficient of thermal expansion e)- final temperature f)- original length

Which one from below is not one of the reasons of planning failures? (clo3) a)-planner is careless. b-planner spend less time in the field but more time on the desk c)-planner is not qualified d)-planner does not have sufficient time to properly plan