Question

A rock with a volume of 2.0m3 is fully submerged in water having a density of 1.0g/cm3. What is the buoyant force acting on the rock?

Answer 1

Given,

Volume of rock(V_R​​​​​​) =2.0m³

Density of water/fluid (ρ_w​​​​​​) =1.0g/cm³=1000kg/m³

^Now,

Using Archimedes’ principle. The buoyant force (F_B​​​​​​) on the rock is equal to the weight of the displaced fluid.

This weight is equal to the mass of the displaced fluid multiplied by the gravitational acceleration:

Therfore,

F_B=M_wg

=ρ_w v_w g

=ρ_w v_R g (as we know volume of the displaced fluid is just the volume of the rock because it is fully submerged )

=1000 (2) (9.8) {all in si unit}

=19600 N