5A solid cylinder of length 10 cm is placed in water. It stands upright with the top 3 cm protruding above the water surface. The density of water is 1.0 g/cm3. What is the density of the cylinder?

Use Archimedes' Principle
Equate the mass of the cylinder to the mass of the water displaced by the cylinder.
Mass = volume x density.
For the cylinder, volume = (cross-sectional area) x length.
For the water, volume = (cross-sectional area)x7.
The cross-sectional area cancels out and we can easily calculate the density of the cylinder. The density is 0.7 g/cm³.
Thanks & Regards
Mukesh Sharma
askIITians Faculty