The decibel scale is logarithmic in intensity:β=10log10II0dB. In this formula, I0 is a reference intensity. To convert the intensity of sound waves from SI units to dB, I0 is taken to be 10−12W/m^2.Once you know the intensity of a source in dB as measured at some reference distance, the intensity at a new distance can be found by subtracting the change in dB appropriate to the ratio of the new distance to the reference distance. The change in dB corresponding to the change in distance may be found by replacing I0 in the formula given here with the intensity at the reference distance and replacing I with the intensity at the new distance. We apply the dB scale to a small firecracker that has an intensity of 140 dB at a distance of 1 m. a) A child sets off the firecracker at a distance of 100 m from the family house. What is the sound intensity β100 at the house?The child's parents are inside the house talking. A typical house attenuates (reduces the intensity of) outside sounds by a factor of around 40 dB--more at high frequencies (when double-pane windows are closed) and less at low frequencies. Also, a typical conversation has an average sound level of 65 dB. b) Will the firecracker sound louder than the parents' conversation?

In a steady-flow steam power plant system, two adiabatic high-pressure and low-pressure turbines ane used to generate power. superheated steam enters the high-pressure turbine at 8 mpa and 550°c. the steam expands in the high-pressure turbine to a saturated vapor at 3 mpa. in order to increase the powe generation of the power plant, another steam turbine working in a lower pressure ranges is deployed. the outlet vapor from the first turbine is heated up at a boiler to the temperature of 500 c at the constant pressure of first turbine's outlet (3 mpa). then, the vapor enters the second turbine and produces extra work. the exit conditions of the second turbine are 5o kpa and 90 percent quality. if the total power output of the power plant is 25 mw, determine a) the mass flow rate of the water (kg/s). b) heat transfer rate in the boiler (mw). (30 points) 3 mpa 00 c 8 mpa s0 c high pres turbine low pres boiler turbine 50 kpa 3 mpa 09 saturated vapor t heat engine, shown in the figure, operates between high temperature and low temperature of through a heat 4. a carnot tn and tu respectively. this heat engine receives energy from a heat reservoir at t exchanger where the heat transferred is proportional to the temperature difference as ? = k (z,-7, ). it rejects heat at a given low temperature tl. to design the heat engine for maximum work output, find the high temperature, th, as a function of tes and t. (15 points) qe

Eddy whose mass is 55kg climbs up the 1.50 meter high stairs in 2s.calculate eddy’s power rating

Which law represents the thermodynamic statement of the conservation of energy of a system? a. the fourth law b. the first law c. the second law d. the third law