P7.17 Consider the vibration absorber in Figure P7.17. 

Using the root locus method, determine the effect of the parameters M2 and k12. Determine the specific values of the parameters M2 and k12 so that the mass

M1 does not vibrate when F t( ) = a t  sin( ) ω0 . Assume that M k 1 1 = = 1, 1, and b = 1. Also assume that

k12 k12 1 may be neglected.

b Force F(t) k M1 k12 y(t) FIGURE P7.17 Vibration absorber. M2 Ty2(1)