Calculate the change in free-energy associated with the formation of a critical spherical nucleus. in pure liquid nickel that is 240 ºC undercooled. The answer should be given in atto-joules with 1 decimal of accuracy. (Note the metric prefix atto is 10-18) Properties of Nickel: Heat of Fusion 2660 J/cm3; Surface Energy 255x10-7 J/cm2 ; Freezing Temperature 1453 ºC, Volume Free Energy -728.99 J/cm3 .

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.

An electrical motor raises a 50kg load at a construct velencity .calculate the power of the motor, if it takes 40sec to raise the load through a height of 24m(take g =9.8n/g)

The mass flow rate of the fluid remains constant in all steady flow process. a)- true b)- false