Analyze the collision of a baseball with a bat. during which portion of the collision does the baseball’s velocity reach zero?

hint: during the collision, the baseball goes from a negative velocity to a positive velocity. at some point, the velocity is zero.

before the collision

during the collision

one second after the collision

one-hundredth of a second after the collision

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)