Density of cylinder that undergoes vertical oscillation

[dobbygenius]

Homework Statement:

A metal cylinder with a height of 14 cm floats in mercury so that it undergoes a vertical oscillation with a period of 0.6 s. What is the mass density of the cylinder?

Relevant Equations:

density of mercury: 13600 kg/m^3

I'm not sure where to start...

 

[haruspex]

Homework Statement:: A metal cylinder with a height of 14 cm floats in mercury so that it undergoes a vertical oscillation with a period of 0.6 s. What is the mass density of the cylinder?
Relevant Equations:: density of mercury: 13600 kg/m^3

I'm not sure where to start...

Start with a diagram showing the cylinder at some displacement from equilibrium.
Next, write an equation for its acceleration.