(1 mark) (b)
Electricity can also be generated in a pumped storage hydroelectric power station
An advantage of pumped storage hydroelectric power stations is the short start-up fime
they have
(b) (i) What is the importance of the short start-up time?
(1 mark)
(b) (ii) Give one other advantage of a pumped storage hydroelectric power station.
(1 mark)

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)

The mass of the sun is 1.99×1030kg and its distance to the earth is 1.50×1011m. what is the gravitational force of the sun on the earth?

Atruck with 34-in.-diameter wheels is traveling at 55 mi/h. find the angular speed of the wheels in rad/min, *hint convert miles to inches & hours to minutes: