Which equation represents the law of conservation of energy in a closed system?
o ke + pe = ke: + pe
pe; + pex = ke + ke
ke - ke = pe - pe
o ke - pe; = pe; - ke
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Two kilograms of air within a piston–cylinder assembly executes a carnot power cycle with maximum and minimum temperatures of 800 k and 300 k, respectively. the heat transfer to the air during the isothermal expansion is 60 kj. at the end of the isothermal expansion the volume is 0.4 m3. assume the ideal gas model for the air. determine the thermal efficiency, the volume at the beginning of the isothermal expansion, in m3, and the work during the adiabatic expansion, in kj.

You are the coordinator for a program that is going to take place at night in a rectangular amphitheater in the mountains. you will have no access to any electricity, but you must be able to illuminate the entire grounds. you know the intensity of the light from a lantern varies inversely as the square of the distance from the lantern. suppose the intensity is 90 when the distance is 5 m. a. write an equation to model the situation. b. solve for the constant of variation. c. write the equation to model the situation using the constant () of variation. d. you have been given lanterns with 40 light intensity. use your equation to solve for the distance from the lantern. e. you need to illuminate 225 km. how many meters do you need to light? f. how many lanterns will you need?

The device shows the relative humidity at 22°c. what’s the water vapor density if the maximum water vapor in air at this temperature is 20 grams/cubic meter? a device showing that at 22 degrees celsius the relative humidity is 58%. a. 11.6% b. 11.6 g/m3 c. 12.76% d. 12.76 g/m3 reset next