A cyclist with a total skin area of 1.5 m^2 is riding a bicycle on a day when the air temperature is 20 degrees Celsius, and her skin temp is 34 degrees celsius. The cyclist does work at about 100W ( moving her pedals ) but her efficiency is only about 20% in terms of converting energy into mechanical work. Estimate the amount of water this cyclist must evaporate per hour (through sweat) to get rid of excess body heat she produces. Assume a skin emissivity of .70