Question 15 (Problem from 9.28 from text): Figure 6 shows the 1/4-car suspension system from Problems 2.30 and 6.23. The input is road position, Zin(t), which is measured with respect to a level road datum. All displacements are measured with respect to their static equilibrium positions. The system parameters are: 14-car mass mi = 250 kg Wheel-axle mass my = 30 kg Suspension spring kj = 1.6(104) N/m Suspension damper coefficient b = 980 N-s/m Tire stiffness ky = 1.6(105) N/m a) Determine the vibration frequencies for an impulsive ("bump") input caused by a sudden displacement of the road. b) Analyze the frequency response of the position of the 1/4-car mass ml using the Bode diagram. In particular, estimate the resonant frequencies and the associated transmissibility for each resonant frequency. 1/4-car mass m1 Z1 Suspension K1 b system Wheel/axle assembly m2 Z2 Zin(1) Level road Figure 3: Model of 1/4 Car Suspension