A40-l electrical radiator containing heating oil is placed in a 60-m3 room as shown in the figure. both the room and the oil in the radiator are initially at 10°c. the radiator with a rating of 2.4 kw is now turned on. at the same time, heat is lost from the room at an average rate of 0.35 kj/s. after some time, the average temperature is measured to be 20°c for the air in the room, and 50°c for the oil in the radiator. taking the density and the specific heat of the oil to be 950 kg/m3 and 2.2 kj/kg·°c, respectively, determine how long the heater is kept on. assume the room is well-sealed so that there are no air leaks. the gas constant of air is r = 0.287

The most important difference between a wedge and an inclined plane is a. their size b. their shape c. how they are used d. what they are made of

An internally reversible refrigerator has a modified coefficient of performance accounting for realistic heat transfer processes of where qin is the refrigerator cooling rate, qout is the heat rejection rate, and is the power input. show that copm can be expressed in terms of the reservoir temperatures tc and th, the cold and hot thermal resistances rt,c and rt,h, and qin, as where rtot rt,c rt,h. also, show that the power input may be expressed as 1.39 a household refrigerator operates with cold- and hot-temperature reservoirs of tc 5 c and th 25 c, respectively. when new, the cold and hot side resistances are rc,n 0.05 k/w and rh,n 0.04 k/w, respectively. over time, dust accumulates on the refrigerator’s condenser coil, which is located behind the refrigerator, increasing the hot side resistance to rh,d 0.1 k/w. it is desired to have a refrigerator cooling rate of qin 750 w. using the results of problem 1.38, determine the modified coefficient of performance and the required power input w under (a) clean and (b) dusty coil conditions. internally reversible refrigerator qout qin w high-temperature reservoir low-temperature reservoir th th,i tc,i tc high-temperature side resistance low-temperature side resistance w qin th tc qinrtot tc qinrtot copm tc qinrtot th tc

Does anyone know how to solve this problem? i really need . i made an attempt but i just cant get it. a metal rod is 25.000 cm long at 25.0 degrees celsius. when heated to 102.0 degrees celsius, it is 25.054 cm long. what is the coefficient of linear expansion for this metal.