Physics - Fluid Question with Solution | TestHub

Both balls have the same volume V, so they displace the same water and experience equal buoyancy.

$$B={\rho }_{\mathrm{water}}Vg$$

$$m_{\mathrm{ball}}={\rho }_{\mathrm{ball}}V$$

$$a=\frac{{\rho }_{\mathrm{ball}}Vg-B}{{\rho }_{\mathrm{ball}}V}$$

$$a=g\left(1-\frac{{\rho }_{\mathrm{water}}}{{\rho }_{\mathrm{ball}}}\right)$$

$${\rho }_{\mathrm{Fe}}>{\rho }_{\mathrm{Al}}\Rightarrow a_{\mathrm{Fe}}>a_{\mathrm{Al}}$$

Released together from the same depth, iron reaches the bottom first (B).