A car has a unibody-type frame and is supported by four suspension springs, each with a force constant of 29600 n/m. the combined mass of the car's frame and everything inside it (the engine, the seats, the passengers, etc.) is 1090 kg. because of worn-out shockabsorbers, the car vibrates up and down every time it is driven over a pothole. what is the frequency of this vibration? answer in units of hz.