Consider steady-state evaporation of a spherical toluene (A), which is evaporating into a very large volume of still air (B). You may assume that the size of the sphere is relatively large and thus remains constant over the timescale of interest.

a. Starting with a shell balance, show that for a concentrated solute, the expression for yA as a function of r is given by:

YA= 1- (1- YA, sat)^Ro/r

(where Ro = radius of sphere, yAsat = equilibrium saturation mole fraction of toluene in air)

b. Using this expression for YA, show that you can recover the expression we derived for a dilute solution

Tom is having a problem with his washing machine. he notices that the machine vibrates violently at a frequency of 1500 rpm due to an unknown rotating unbalance. the machine is mounted on 4 springs each having a stiffness of 10 kn/m. tom wishes to add an undamped vibration absorber attached by a spring under the machine the machine working frequency ranges between 800 rpm to 2000 rpm and its total mass while loaded is assumed to be 80 kg a) what should be the mass of the absorber added to the machine so that the natural frequency falls outside the working range? b) after a first trial of an absorber using a mass of 35 kg, the amplitude of the oscillation was found to be 10 cm. what is the value of the rotating unbalance? c) using me-3.5 kg. m, find the optimal absorber (by minimizing its mass). what would be the amplitude of the oscillation of the absorber?