In a system with two degrees of freedom, mass is M1-0.25 MNs2/m+student number last digit, M2-0.125MNs2/m+ student number last digit, spring stiffness is k1 = 60MN/m+ student number is first digit, k2=40MN. /m+ the first digit of student number. Then; a) Determine Natural Frequencies and Mode shapes. b) Calculate the earthquake force using the mode combination method using the spectrum curve below. Salg S/g=(0.1+T) e Time Period, T (sec) -X m2 k2 m1 k1