Question

a piece of aluminium and iron weighted 22g and 80g respectively. both have same volume, if aluminium is emerge in water it weighted 10g less. So if iron tied wiht a string and emerge in water what will be upthrust act on i

Answer 1

$$\begin{gathered} \mathrm{The}\mathrm{upthrust}\mathrm{on}\mathrm{the}\mathrm{piece}\mathrm{of}\mathrm{aluminium}=10\mathrm{g}. \\ \mathrm{When}\mathrm{a}\mathrm{piece}\mathrm{of}\mathrm{iron}\mathrm{tied}\mathrm{with}\mathrm{this}\mathrm{aluminium}\mathrm{is}\mathrm{emerged}\mathrm{in}\mathrm{water}, \\ \mathrm{the}\mathrm{upthurst}=10\times 981=9810\mathrm{dyne}. \\ \mathrm{This}\mathrm{is}\mathrm{because}\mathrm{the}\mathrm{volume}\mathrm{of}\mathrm{aluminium}\mathrm{emmerged}\mathrm{in}\mathrm{water}\mathrm{is}\mathrm{the}\mathrm{same}. \\ \mathrm{So}\mathrm{upthrust}\mathrm{is}\mathrm{also}\mathrm{the}\mathrm{same}. \end{gathered}$$