Acertain sprinter has a top speed of 10.6 m/s. if the sprinter starts from rest and accelerates at a constant rate, he is able to reach his top speed in a distance of 11.9 m. he is then able to maintain his top speed for the remainder of a 100 m race. (a) what is his time for the 100 m race? (b) in order to improve his time, the sprinter tries to decrease the distance required for him to reach his top speed. what must this distance be if he is to achieve a time of 10.4 s for the race?

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)