Consider a cooker without cover that holds 1000 ml of water at 25C and lbar. Heat is supplied to the cooker at a rate of 900W while pressure remains constant. After a period of time, the boiling point of water is reached and it continues to boil until all of the water has evaporated. Assuming the kinetic and potential energies of the streams are negligible. Determine: (8 points) 1.The work done by the system in kJ?
2.The time needed for the evaporation process to start in min?
3.The time needed for all of the water to convert to vapor in min?​

On a average work day more than work place firs are reorted

Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.

Apipe with an outside diameter of 15 cm is exposed to an ambient air and surrounding temperature of -20°c. the pipe has an outer surface temperature of 65°c and an emissivity of 0.85. if the rate of heat loss from the pipe surface is 0.95 kw per meter of length, the external convective heat transfer coefficient (h) is: (a) 12.5 w/m"k (b) 18.6 w/mk (c) 23.7 w/mk (d) 27.9 w/mk (e) 33.5 w/mk