A thin partition divides a thermally insulated vessel into a lower compartment of volume V and an upper compartment of volume 2V. The lower compartment contains n moles of an ideal gas; the upper part is evacuated.
When the partition is removed, the gas expands and fills both compartments.
How many moles n of gas were initially contained in the lower compartment if the entropy change of the gas in this free-expansion process is 17.28 J/K?

An object moves from the position +34m to the position -15m in 15 seconds. what is it's total displacement? what is it's average velocity?

Steam is generated in a boiler of a cogeneration plant at 10 mpa and 450°c at a steady rate of 5 kg/s. in normal operation, steam expands in a turbine to a pressure of 0.5 mpa and is then routed to the process heater, where it supplies the process heat. steam leaves the process heater as a saturated liquid and is pumped to the boiler pressure. in this mode, no steam passes through a condenser, which operates at 20 kpa. (a) determine the power produced in the turbine and the rate at which process heat is supplied in this mode. (b) determine the power produced in the turbine and the rate of process heat supplied if only 60 percent of the steam is routed to the process heater and the remainder is expanded to the condenser pressure. (3.32 mw; 9.69 mw; 4.25 mw; 5.82 mw)

In which of the following is positive work done by a person on a suitcase