The natural frequencies of a 3 degree of freedom spring - mass system are given by the solution of the equation a-5a + 6a - 1 = 0 where a = mw m is the mass, wo is the natural frequency, and k is the spring stiffness. a) Plot the cubic polynomial given above to have a better understanding of the possible solutions in a that make the equation equal to zero. b) Use the function polyroot in Mathcad to find the values of a that make the polynomial equal to zero. You cand check the root values with other methods of solution for roots. Find the natural frequency w corresponding to each value of o, knowing that the spring- mass system shown has m = 2.5 kg and k = 100 N/m. ais dimensionless. c) Fin 111