Question

An object volume 4m is totally immersed in a liquid of density 1030kgm. Calculate the upthrust of liquid on the object. A body has mass 10kg in air and 4kg when immersed totally in water. Calculate the volume of the body and its density.

Answer 1

The upthrust is the difference between the weight and buoyancy force:

$$U=mg-\rho_l gV=40.3\text{ kN}.$$

The volume is 4 cubic meters, as stated in the condition. The density is

$$\rho=\dfrac{m}{V}=1\text{ kg/m}^3.$$