Recall that, in a parallel-plate waveguide, any mode that is below cutoff (f < fc) will not propagate but instead be attenuated in the z direction. This means that a properly designed section of waveguide may be used as a filter to select only lower-order modes while attenuating all the higher-order modes. Assume that a section of a parallel-plate air-filled waveguide with a plate separation of 7.11 mm is to be used at 15 GHz as a filter. The waveguide should attenuate all of the modes except the TEM mode as it propagates along the guide. Find the minimum length of waveguide needed to attenuate all higher-order modes (m

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.

If a particle moves along a path such that r : (3 sin t) m and ? : 2t rad, where t is in seconds. what is the particle's acceleration in m/s in 4 seconds? a)- 16.43 b)- 16.29 c)- 15.21 d)- 13.79

Ariver flows from north to south at 8 km/h. a boat is to cross this river from west to east at a speed of 20 km/h (speed of the boat with respect to the earth/ground). at what angle (in degrees) must the boat be pointed upstream such that it will proceed directly across the river (hint: find the speed of the boat with respect to water/river)? a 288 b. 21.8 c. 326 d. 30.2