thank you all. You have been very helpfull. The homework was to make a project summary of something new in this world and this project must be used for applying for research funding so i made up resonant weapon. the other task was to ask people if they know what is and if they can, to find a problem in this resonant weapon for which it cannot be funded this research. for that reason i am thankfull to swanson for finding a problem in the counterbalance in buildings.
yes it is kind of weapon that can equilize the frequency of the building with the frequency of the weapon`s oscillations in which case the buildings are demolished. However, as you said some buildings have counter balance.
