An experimental device that produces excess heat is passively cooled. The addition of pin fins (cylindrical fins) to the casing of this device is being considered to augment the rate of cooling. Consider a copper pin fin 0.25cm in diameter that protrudes from a wall at 95degC into ambient air at 25degC. The natural convection coefficient of the air is 10 W/m2-K. Calculate the heat loss assuming first that the fin is infinitely long, then assuming the fin is 2.5cm long and the coefficient at the end is the same as around the circumference. How long would the fin have to be for the infinitely long solution to be correct within 5%

Many machines- including inclined planes such as ramps- increase the strength of the force put into the machine but decrease the distance over which the force is applied. true or false

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Newton's law of cooling states that the rate of change in the temperature t(t) of a body is proportional to the difference between the temperature of the medium m(t) and the temperature of the body. that is, startfraction dt over dt endfraction equals upper k left bracket upper m left parenthesis t right parenthesis minus upper t left parenthesis t right parenthesis right bracket , where k is a constant. let kequals0.04 left parenthesis min right parenthesis superscript negative 1 and the temperature of the medium be constant, m(t) font size decreased by 3 equivalent font size decreased by 3 294 kelvins. if the body is initially at 369 kelvins, use euler's method with hequals0.1 min to approximate the temperature of the body after (a) 30 minutes and (b) 60 minutes.