An isolated power system with a 600MVA generating unit having M (angular moment of the machine) of 7.6 pu MWpu freq/sec on a machine base The unit is supplying a load of 400MVA The load changes by 2% for a 1% change in frequency.  If the load suddenly increases by 20 MVA.

Determine using a 1000 MVA base 

i. Change in frequency Ao (s).

ii. Change in frequency Aco (t).

iii. Final value of change in frequency.