Atransformer that is 10 cm long, 6.2 cm wide, and 5 cm high is to be cooled by attaching a 10-cm6.2-cm wide polished aluminum heat sink (emissivity 0.03) to its top surface. the heat sink has seven fins, which are 5 mm high, 2 mm thick, and 10 cm long. a fan blows air at 25â°c parallel to the passages between the fins. the heat sink is to dissipate 12 w of heat and the base temperature of the heat sink is not to exceed 60â°c. assuming the fins and the base plate to be nearly isothermal and the radiation heat transfer to be negligible, determine the minimum free-stream velocity the fan needs to supply to avoid overheating.

What is the heat treatment of metals? what is the benefit of it? why and how it's useful? answer in details, do not write by hand.

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?

The process in which the system pressure remain constant is called a)-isobaric b)-isochoric c)-isolated d)-isothermal