Apulsar is a rapidly rotating neutron star that emits a radio beam the way a lighthouse emits a light beam. we receive a radio pulse for each rotation of the star. the period t of rotation is found by measuring the time between pulses. suppose a pulsar has a period of rotation of t = 0.0452 s that is increasing at the rate of 4.69 x 10-8 s/y. (a) what is the pulsar's angular acceleration alpha? (b) if alpha is constant, how many years from now will the pulsar stop rotating? (c) suppose the pulsar originated in a supernova explosion seen 714 years ago. assuming constant alpha, find the initial t.

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)