Check
which statements accurately describe sound waves? check all that apply.
sound waves are transverse waves.
sound waves require a medium to transfer energy.
sound is heard when a vibration strikes the ear.
sound waves can only travel through liquids and gases.
when particles of a medium interact, part of the wave's energy is lost.
a wave's energy can be distinguished from other movements of the medium.

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)