Acylindrical casting has a diameter of 300 mm and a length of 1 m. another casting of the same metal is rectangular in cross-section, with a width-to-thickness ratio of 3, and has the same length and cross-sectional area as the round casting. both pieces are cast under the same conditions. the cylindrical casting solidifies in three minutes. how long does the rectangular crosssection casting take to solidify?

Acatapult is tested by roman legionnaires. they tabulate the results in a papyrus and 2000 years later the archaeological team reads (distances translated into modern units): range = 0.4 km; angle of launch = π/5 rad; landing height = launch height. what is the initial velocity of launch of the boulders if air resistance is negligible?

If angle "a" is 25°, angle "b" is: a) equal to angle c b) less than angle c c) greater than angle c

Air enters a gas turbine with two stages of compression and two stages of expansion at 100 kpa and 17°c. this system uses a regenerator as well as reheating and intercooling – the intercooler returns the air to the inlet temperature. the pressure ratio across each compressor is 4 ; 300 kj/kg of heat are added to the air in each combustion chamber; and the regenerator operates perfectly while increasing the temperature of the cold air by 20°c. determine the system’s thermal efficiency. assume isentropic operations for all compressor and the turbine stages and use constant specific heats at room temperature. (0.378)