When an exhaust fan of mass \(380 \mathrm{~kg}\) is supported on springs with negligible damping, the resulting static deflection is found to be \(45 \mathrm{~mm}\). If the fan has a rotating unbalance of \(0.15 \mathrm{~kg}-\mathrm{m}\), find (a) the amplitude of vibration t \(1750 \mathrm{rpm}\), and (b) the force transmitted to the ground at this speed.