Sophia veut vendre un bracelet en or massif. Elle se renseigne sur le prix de lor ET apprend qu un kilogramme d ir coute 38100€. Son bracelet a pour volume 1,81cm³. Calcule le prix de l or constituant le bracelet de Sophia.
Donnee
Masse volumique de l or:
Ro or = 19300kg/m³

Anybody wanna ? (picture included? )

Air is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. air enters the heat exchanger at 95 kpa and 20°c at a rate of 0.6 m^3/s. the combustion gases (cp = 1.10 kj/kg°c) enter at 160°c at a rate of 0.95 kg/s and leave at 95°c. determine the rate of heat transfer to the air and its outlet temperature.

You have a resistor and a capacitor of unknown values. first, you charge the capacitor and discharge it through the resistor. by monitoring the capacitor voltage on an oscilloscope, you see that the voltage decays to half its initial value in 3.00 ms . you then use the resistor and capacitor to make a low-pass filter. what is the crossover frequency fc?