A fan, an electric motor turns the fan with 1500 RPM speed, and the platforms are together 920 kg. 4 vibration isolators will be placed to deny the vertical force[F(t)=F(0)coswt] which occurs because of unbalance. We want the vertical force to decrease 10% of initial [Another words, we want it decrease 90%]. Then, calculate the spring and damping specifications of isolators that can be used. Make a research in market and find and choose those isolators as brand, type and price. When these isolators are used, draw the transmittence-frequency curve of this system.