The graph shows the acceleration, velocity, and displacement of a marble attached to a metal spring that has been secured to a tabletop. the marble was pulled down to the floor and then released. which is true about the marble's motion? motion and forces a. when acceleration is at a minimum, displacement is also at a minimum. b. when acceleration is at a minimum, velocity is at a maximum. c. when velocity is zero, displacement is at a maximum. d. when velocity at a maximum, acceleration is also at a maximum.

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)