Question

A tractor seat is mounted on springs. When a 78 kg adult sits on the seat, the characteristic frequency is 3 Hz. What is the characteristic frequency when a child of mass 22 kg sits on the seat? (Neglect the seat mass.)

Answer 1

$$f=\frac{1}{2\pi}\sqrt{\frac{k}{m}}$$

So,

$$f'=f\sqrt{\frac{m}{m'}}=3\sqrt{\frac{78}{22}}=5.65\ Hz$$