Ahockey puck is sliding along the ice with nearly constant momentum ‹ 7, 0, 4 › kg · m/s when it is suddenly struck by a hockey stick with a force ‹ 0, 0, 2100 › n that lasts for only 7 milliseconds (7×10−3) s. what is the new momentum of the puck?

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)