Two billiard balls with identical masses and moving in opposite directions have a 100 % elastic (perfect bounce)
head-on collision. Before the collision, each ball has a
speed of 21.9 cm/s. Find the speed of each billiard ball
immediately after the collision.
(hint: total mo = o before they collide)

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)