how do positive and negative acceleration differ? 1. positive acceleration represents an object speeding up; negative acceleration represents an object slowing down 2. positive acceleration moves North or east; negative acceleration moves south or west 3. positive acceleration occurs when there is more velocity than speed; negative acceleration occurs when there is less velocity than speed. 4. positive acceleration occurs when an object changes its speed but not its direction; negative acceleration occurs when an object changes both its speed and direction

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)