Calculate the frequency spectrum of sound power radiating from a thin/thick plate or shell under the following conditions. (1)you can arbitrarily choose vibrating plate or shell. (2)you are expected to execute modal analysis, forced vibration analysis and estimation of sound radiation power however you can assume any mode shapes or natural frequencies if it will be difficult to calculate exact or approximated vibration modes. (3) you can select mechanical point excitation or sound excitation with arbitrary frequency spectrum of excitation force. (4) you also assume modal total loss factors even if they are constant. (5) illustrate mode shapes with natural frequencies and frequency spectra of loss factors, input power and sound radiation power.

Amajor impediment to wide acceptance of electric vehicles even on the part of people who use their cars almost exclusively for commuting is the inability to use their electric vehicles for occasional extended trips. in an attempt to make purchasing electric vehicles more attractive to commuters, one electric vehicle producer is planning to offer customers three days free rental of a conventional car for every 1,000 miles that they drive their electric vehicle. which of the following, if true, most threatens the plan's prospects for success? (a) many electric vehicles that are used for commercial purposes are not needed for extended trips. (b) because a majority of commuters drive at least 100 miles a week, the cost to the producer of making good the offer would add considerably to the already high price of electric vehicles. (c) the relatively long time it takes to recharge the battery of an electric vehicle can easily be fitted into the regular patterns of car use characteristic of commuters. (d) although electric vehicles are essentially emission-free in actual use, generating the electricity necessary for charging an electric vehicle's battery can burden the environment. (e) some family vehicles are used primarily not for commuting but for making short local trips, such as to do errands.