Question

There are 2 blocks of same volume and shape, one is of mass 3 kg(it is wood) and other is of mass 5 kg(it is iron).Which of the two blocks will experience more upthrust in a given liquid??

Answer 1

Sol: Upthrust force, which is also said to be buoyancy force, exerted by a liquid is always equals to the weight of the liquid
that is displaced by the body while immersing it into the liquid.
$$\begin{gathered} Ifthemassoftheliquid,displacedbythebodyis\text{'}m\text{'},thenupthrustforce \\ exertedbyliquidwillbe: \\ {F}_B=W_{liq}=mg=\rho \times V\times g[mass=density\times volume] \\ therefor \\ {F}_B\alpha v[asdensityofliquid\text{'}\rho \text{'}issameinbothcasesand \\ acc.duetogravity\text{'}g\text{'}iscons\tan t] \\ Inboththecasesstatedabove(forwoodenandironblock)volumeissame, \\ thereforbothwillexperiencesameupthrustforcebyliquid. \end{gathered}$$