1. If the air in a 12-in diameter duct with an air flow of 1,500 ft /min and a velocity of 14 ft/min flows into a 6-in diameter duct, what are the new flow rate and velocity? Show all work. (20 pts) 2. If an employee is exposed to continuous sound levels for 2 hours at 95 dB and is then exposed to sound levels below 65 dB for the rest of the 8-hour day, what is the employee's 8 hour TWA in dBA using OSHA's calculations? Does this employee exceed OSHA's PEL? Does this employee need to be in a hearing conservation program? Show all work. (20 pts) 3. Complete the following table with the appropriate molecular weights for each chemical and convert the following concentrations from parts per million (ppm) to milligrams per meter (mg/ms) or from mg/m3 to ppm. Show all work. (20 pts) CHEMICAL MW PPM MG/M3 Toluene 92 100 376 MEK 72 29 85 Methanol 32 750 982 Trichloroethylene 131 25 134 Dichlorodifluoromethane 120 202 1000 Ethylbenzene 106 120 520 4. An employee needs to lose 724 BTU/hr through evaporation in order to maintain a body temperature of 98.6 .F. The outdoor air temperature is 84 .F and the water vapor pressure is 35 mm Hg with a wind speed of 12mph. What is the heat stress index? Show all work. (20 pts) 5. The exposure rate 5ft from a certain gamma-ray source is 200 mR/h. At what distance from the source does the exposure rate fall to 2 mR/h? Show all work. (20 pts)