A) Halley's comet orbits the sun about every 75 years due to the gravitational force the sun provides. Compare the gravitational force between halley's Comet and the sun when the comet is at aphelion (its greatest distance from the sun) and d is about 4.5 x 10^10 m to the force at perihelion (or closest approach), where d is about 5.0 x 10^10 m. B) In part A, what is the comet's acceleration a) at aphelion? b) at perihelion? (M of the sun=1.99 x 10^30)

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Natural forces that can alter ecosystems include seasons and climate changes. t or f

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)

Astudent creates a model of a closed ecosystem by filling a glass tank half full with water, then adding 10 snails and two small aquatic plants. the next day, all the snails are dead. what is the most likely cause of their death?