A sphere falls from rest into water from a height of 2 m. The relative density of the sphere is 0.80. Find the depth to which ball will sink (in m).

Velocity of the ball when reaches surface of
water$v=\sqrt{2gh}=\sqrt{4g}$

Acceleration inside the water

$\mathrm{a}=\frac{\text{ apparent weight }}{\mathrm{m}}$

$=\frac{\mathrm{mg}\left(1-\frac{\sigma }{\rho }\right)}{\mathrm{m}}=\mathrm{g}\left(1-\frac{1}{0.8}\right)=-\frac{\mathrm{g}}{4}$

Let it goes to a depth x, then using $v^2=u^2+2as$

$\Rightarrow 0=4g-2\times \frac{g}{4}\times x\Rightarrow x=8m$