Asquare aluminum plate 5 mm thick and 200 mm on a side is heated while vertically suspended in quiescent air at 40c. (a) determine the average heat transfer coefficient for the plate when its temperature is 15c by two methods: using results from the similarity solution to the boundary layer equations, and using results from an empirical correlation. (b) calculate the convective heat transfer loss to the air from both surfaces (c) calculate the net radiation heat loss to a very large environment at 35c. assume it is a two surface enclosure and all surfaces are gray and diffuse. e=1.0. do you think you can neglect the radiation heat loss?

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?