The seed crystal used for czochralski crystal growth is necked down to about 3 mm diameter to produce a dislocation-free crystal. use 2 x 10^6 g/cm2 as the yield strength of silicon at the growth temperature (the units are strange but correct assuming the gravitational constant of earth, etc.) and determine the maximum length of each ingot that can be supported by this neck if the ingots are 150, 200 and 300 mm diameter.
for the 200 mm diameter case, how many wafers can be produced (if the final wafer thickness is 725 mm).

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?