A switch-mode dc-dc converter is operating at a switching frequency of 20 kHz, and Vd ¼ 150 V. The average current being drawn by the dc motor is 8.0 A. In the equivalent circuit of the dc motor, Ea ¼ 100 V, Ra ¼ 0:25 Ω, and La ¼ 4 mH, all in series.
(a) Plot the output current and calculate the peak-to-peak ripple and
(b) plot the dc-side current.

Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.