g With aerodynamic resistance considered (using Eq. 2.42), SS= bbWW 2ggKKaa (1+ KKaaVV1 2 WW(bbµµ+ff±sinθθgg) ) = • For the same conditions but with bb ′ =0.85, Eq. 2.42 gives SS= bbWW 2ggKKaa (1+ KKaaVV1 2 WW(bbµµ+ff±sinθθgg) ) = • Now applying Eq. 2.47 (or Eq. 2.46 since GG=0) for the practical stopping distance, dd = VV1 2 2gg( aa gg±GG) = • In the first case, the difference is ; • In the case of 85% braking efficiency, the difference is .

Ahot wire operates at a temperature of 200°c while the air temperature is 20°c. the hot wire element is a tungsten wire of 5 um diameter and 2 mm in length. plot using excel current, heat transfer and heat generated by the wire for air velocity varying from 1-10 m/s in steps of lm/s? matlab the sensor voltage output, resistance, or assume nu 0.989 re033pr13 take air properties at tr (200°c20°c)/2 = 110°c properties of tungsten: c 0.13 kj/kg.k 3 p 19250 kg/m k (thermal conductivity) = 174 w/m.k

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Air at a pressure of 1atm and a temperature of 40 c is in parallel flow over the top surface of a flat plate that is heated to a uniform temperature of 120 c. the plate has a length of 0.40m (in the flow direction) and a width of 0.15m. the reynolds number based on the plate length is 50, 000. what is the rate of heat transfer from the plate to the air? if the free stream velocity of the air is doubled and the pressure is increased to 10 atm what is the rate of heat transfer?