Question

which object will sink in freshwater, which has a density of 1.0 g/cm³?
object 1, which has a density of 0.8 g/cm³
object 2, which has a density of 1.0 g/cm³
object 3, which has a density of 0.6 g/cm³
object 4, which has a density of 0.3 g/cm³

Explanation:

Step1: Recall the density - sinking/floating rule

An object sinks in a fluid if its density \(
ho_{object}>
ho_{fluid}\).

Step2: Compare the densities of each object with the density of freshwater

• For Object 1: \(

ho_{1} = 0.8\ g/cm^{3}\), and since \(0.8\ g/cm^{3}<1.0\ g/cm^{3}\), it will float.

• For Object 2: \(

ho_{2}=1.0\ g/cm^{3}\), it will be in neutral - buoyancy (neither sink nor float freely, just stay at the level it is placed).

• For Object 3: \(

ho_{3}=1.8\ g/cm^{3}\), and since \(1.8\ g/cm^{3}>1.0\ g/cm^{3}\), it will sink.

• For Object 4: \(

ho_{4}=0.3\ g/cm^{3}\), and since \(0.3\ g/cm^{3}<1.0\ g/cm^{3}\), it will float.

Answer:

Object 3, which has a density of \(1.8\ g/cm^{3}\)