A body can move in a circle at constant speed if A. net radial forces equal net tangential forces. B. there is an unbalanced radial force directed inwards. C. all the statements above are correct. D. inward and outward forces are equal in magnitude. E. none of the statements above are correct.

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)